Silent corticotroph adenomas

The 2022 WHO classification of tumors of the pituitary gland: An update on aggressive and metastatic pituitary neuroendocrine tumors

The vast majority of pituitary neuroendocrine tumors (PitNETs) are benign and slow growing with a low relapse rate over many years after surgical resection. However, about 40% are locally invasive and may not be surgically cured, and about one percentage demonstrate an aggressive clinical behavior. Exceptionally, these aggressive tumors may metastasize outside the sellar region to the central nervous system and/or systemically. The 2017 (4th Edition) WHO Classification of Pituitary Tumors abandoned the terminology "atypical adenoma" for tumors previously considered to have potential for a more aggressive behavior since its prognostic value was not established. The 2022 (5th Edition) WHO Classification of the Pituitary Tumors emphasizes the concept that morphological features distinguish indolent tumors from locally aggressive ones, however, the proposed histological subtypes are not consistent with the real life clinical characteristics of patients with aggressive tumors/carcinomas. So far, no single clinical, radiological or histological parameter can determine the risk of growth or malignant progression. Novel promising molecular prognostic markers, such as mutations in ATRX, TP53, SF3B1, and epigenetic DNA modifications, will need to be verified in larger tumor cohorts. In this review, we provide a critical analysis of the WHO guidelines for prognostic stratification and diagnosis of aggressive and metastatic PitNETs. In addition, we discuss the new WHO recommendations for changing ICD-O and ICD-11 codes for PitNET tumor behavior from a neoplasm either "benign" or "unspecified, borderline, or uncertain behavior" to "malignant" neoplasm regardless of the clinical presentation, histopathological subtype, and tumor location. We encourage multidisciplinary initiatives for integrated clinical, histological and molecular classification, which would enable early recognition of these challenging tumors and initiation of more appropriate and aggressive treatments, ultimately improving the outcome.

E-cadherin expression and gene expression profiles in corticotroph pituitary neuroendocrine tumor subtypes

Corticotroph adenomas/pituitary neuroendocrine tumors (PitNETs) are associated with significant morbidity and mortality. Predictors of tumor behavior have not shown high prognostic accuracy. For somatotroph adenomas/PitNETs, E-cadherin expression correlates strongly with prognosis. E-cadherin expression has not been investigated in other PitNETs. A retrospective chart review of adults with corticotroph adenomas/PitNETs was conducted to assess correlation between E-cadherin expression and tumor characteristics. In addition, gene expression microarray was performed in subset of tumors (n = 16). Seventy-seven patients were identified; 71% were female, with median age of cohort 45.2 years. Seventy-five percent had macroadenomas, of which 22% were hormonally active. Ninety-five percent of microadenomas were hormonally active. Adrenocorticotropic hormone granulation pattern by IHC identified 63% as densely granulated (DG) and 34% as sparsely granulated (SG). All microadenomas were DG (p < .001); 50% of macroadenomas were DG associated with increased tumor invasion compared to SG. E-cadherin IHC was positive in 80%, diminished in 17%, and absent in 20% and did not correlate with corticotroph PitNETs subtype, size, or prognosis. In contrast to the distinct transcriptomes of corticotroph PitNETs and normal pituitaries, a comparison of clinically active and silent corticotroph PitNETs demonstrated similar molecular signatures indicating their common origin, but with unique differences related to their secretory status.

The clinicopathological features and prognosis of silent corticotroph tumors: an updated systematic review and meta-analysis

INTRODUCTION

Data on silent corticotroph tumor (SCT) are still heterogeneous and controversial. In this study, we aimed to compare the demographic, clinicopathological manifestations, postoperative complications, and patient outcomes of SCTs with other non-functioning pituitary neuroendocrine tumor (NFT) and functioning corticotroph tumor (FCT) or so-called Cushing disease adenoma.

METHODS

We searched PubMed and Web of Science for data of interest. Odds ratio (OR), mean difference (MD), hazard ratio (HR), and their 95% confidence intervals (CI) were pooled using the random-effect model.

RESULTS

Twenty-nine studies with 985 SCTs were included in meta-analyses. In comparison to other NFTs, SCTs were more commonly associated with female gender, younger age, cavernous sinus invasion, apoplexy, and radiotherapy administration. Postoperatively, SCT patients were more likely to experience hypocortisolism, new-onset visual disturbances, and a higher risk for tumor progression than other NFTs. We did not find any significant differences between SCT type I and type II. Compared to FCTs, SCTs were more likely male, older age, and had larger tumor sizes. The prevalence of a USP8 mutation was significantly higher in FCT than in SCT.

CONCLUSION

SCT was demographically, clinicopathologically, and prognostically distinct from other NFTs and FCTs. These tumors should be considered high-risk; appropriate treatment decisions and more stringent follow-up should be tailored to improve patient outcomes.

Cystic versus non-cystic silent corticotrophic adenomas: clinical and histological analysis of 62 cases after microscopic transsphenoidal surgery-a retrospective, single-center study

Silent corticotrophic adenomas (SCAs) represent a rare group of non-functioning adenomas with a potentially aggressive clinical course. Cystic component is a very common finding among SCAs, but its clinical relevance has not yet been investigated. The aim of this study was to analyze clinical features of cystic and non-cystic SCAs, perioperative complications after microscopic transsphenoidal surgery, clinical outcome after first and repeat surgery along with risk factors for recurrence. We conducted a retrospective analysis of 62 silent corticotrophic adenomas treated at our university medical center via microscopic transsphenoidal surgery between January 2008 and July 2019. Parameters investigated included histology, invasiveness, intratumoral haemorrhage or cystic component on MRI, perioperative alteration of visual field, tumor size, pre- and postoperative ACTH, FSH, GH, LH, TSH, prolactin, cortisol, free T4, free T3, IGF-1, estrogen and testosterone levels, perioperative complications, neoadjuvant and adjuvant therapy along with clinical outcomes. A total of 62 patients were analyzed. The mean follow up was 28.3 months. Tumors with a cystic component occur statistically significant more often among male than non-cystic (80.6% vs. 44.4%, p = 0.02) and display lower rates of cavernous sinus invasion and sphenoid sinus invasion were significantly lower for cystic lesions comparing to non-cystic tumors (42.3% vs. 69.4%, p = 0.04 and 3.8% vs. 47.2%, p < 0.001). GTR after MTS was not statistically significant higher by cystic SCAs (80% vs. 57.1%, p = 0.09). Cystic lesions were also associated with higher risk of hyperprolactinemia (19.4% vs. 2.8%, p = 0.02) and only densely granulated cystic SCAs presented with preoperative intratumoral hemorrhage (19.2% vs. 0%, p = 0.01). Mean duration of first surgery was significantly shorter for cystic SCAs (71.6(± 18.7) vs. 94.8(± 31.1) minutes, p = 0.01). Preoperative pituitary insufficiency (25% vs. 16.7%, p = 0.49), intraoperative CSF space opening (21.1% vs. 37.5%, p = 0.32), along with postoperative new pituitary insufficiency (15% vs. 10%, p = 0.67) or diabetes insipidus/SIADH (10% vs. 13.3%, p > 0.99) with histological markers such as Ki67 (21.1% vs. 13.8%, p = 0.70) and p53 expression (6.3% vs. 0%, p = 0.39) as well as mitotic rate (5.3% vs. 10.3%, p > 0.99) were comparable between both groups. The presence of cystic component did not affect the tumor recurrence (10% vs. 16%, p = 0.68). Mean duration of surgery was first surgeries was not statistically shorter than repeat surgeries (85.4 ± 29.1 vs. 93.8 ± 28 min, p = 0.15). Patients undergoing first surgery had a higher probability of gross total resection (74.4% vs. 30%, p = 0.01) and lower probability of intraoperative CSF space opening (26% vs. 58.3%, p = 0.04) as well as a lower rate of preoperative anterior pituitary insufficiency (20% vs. 58.3%, p = 0.01). The incidence of new postoperative anterior pituitary insufficiency (10% vs. 0%, p = 0.57) and transient diabetes insipidus/SIADH (12% vs. 8.3%, p > 0.99) between those groups were comparable. No statistical difference was observed between patients with remission and with recurrent tumor regarding cortisol and ACTH levels, incidence of different histological subgroups, invasively growing tumors and lesions with cystic components as well as the percentage of cases with increased Ki67 proliferation index, p53 expression and mitotic indices. Our study presents one of the largest available cohorts of SCAs after microscopic transsphenoidal surgery and first clinical analysis of cystic versus non-cystic SCAs so far. We also performed the first comparison of index and repeat surgeries for this tumor entity. Cystic tumors presented with characteristic clinical aspects like male predominance, higher risk of hyperprolactinemia as well as lower rates of cavernous sinus and sphenoid sinus invasion comparing to non-cystic lesions. Mean duration of first surgery was significantly shorter for cystic SCAs. Moreover preoperative intratumoral hemorrhage had 100% specificity and 60% sensitivity for densely granulated cystic SCAs. All these clinical hallmarks may suggest a novel subgroup of SCAs with distinct clinical and biological features, however further clinical and molecular investigations are required. Second surgeries are associated with a higher incidence of preoperative pituitary insufficiency, and a higher risk of subtotal resection, and a higher probability of CSF space opening intraoperatively compared to first surgeries. On the other hand, the risk of new postoperative pituitary insufficiency was higher after first surgeries. In our cohort of patients, no prognostic factor for recurrence among histological diagnosis, Ki67-proliferation index, p53 expression, number of mitoses, invasive growth or cystic lesions for SCAs could be detected.

Aggressive nonfunctioning pituitary neuroendocrine tumors

Nonfunctioning pituitary neuroendocrine tumors (NF-PitNETs) are tumors that are not associated with clinical evidence of hormonal hypersecretion. According to the World Health Organization (WHO), there are some subtypes of PitNETs that exhibit more aggressive behavior than others. Among the types of potentially aggressive PitNETs, three are nonfunctional: silent sparsely granulated somatotropinomas, silent corticotropinomas, and poorly differentiated PIT-1 lineage tumors. Several biological markers have been investigated in NF-PitNETs. However, there is no single biomarker able to independently predict aggressive behavior in NF-PitNETs. Thus, a more complex and multidisciplinary proposal of a comprehensive definition of aggressive NF-PitNETs is necessary. Here, we suggest a combined and more complete criterion for the NF-PitNETs classification. We propose that aggressiveness is due to a multifactorial combination, and we emphasize the need to include new emerging markers that are involved in the aggressiveness of NF-PitNETs and the need to identify.

Silent Corticotroph and Somatotroph Double Pituitary Adenoma: A Case Report and Review of Literature

Clinically silent double pituitary adenomas consisting of corticotroph and somatotroph cells are an exceedingly rare clinical finding. In this report, we present the case of a 28-year-old man with a 1-year history of recurrent headaches. Imaging revealed a 2.1 (anterior-posterior) × 2.2 (transverse) × 1.3 (craniocaudal) cm pituitary adenoma invading into the left cavernous sinus and encasing the left internal carotid artery. Endoscopic transnasal resection was performed without complications. Immunohistochemical staining revealed a double adenoma consisting of distinct sparsely granulated somatotroph and densely granulated corticotroph cells that were positive for growth hormone and adrenocorticotropic hormone, respectively. K _i -67 index labeling revealed a level of 6% within the corticotroph adenoma. No increase in serum growth hormone or adrenocorticotropic hormone was found, indicating a clinically silent double adenoma. While transsphenoidal surgery remains a first-line approach for silent adenomas presenting with mass effects, increased rates of proliferative markers, such as the K _i -67 index, provide useful insight into the clinical course of such tumors. Determining the K _i -67 index of silent pituitary adenomas could be valuable in predicting recurrence after initial surgical resection and identifying tumors that are at an increased risk of needing additional therapeutic interventions or more frequent surveillance imaging.

Clinical Course and Unique Features of Silent Corticotroph Adenomas

OBJECTIVE

Silent corticotroph adenomas (SCAs) behave more aggressively than other non-functioning adenomas (NFAs). This study aims to expand the body of knowledge of the behavior of SCAs.

METHODS

Retrospective analysis of 196 non-corticotroph NFAs and 20 SCAs from 2012-2017 was completed. Demographics, clinical presentation, imaging, and biochemical data were gathered. The primary endpoint was to identify features of SCAs versus other NFAs that suggest aggressive disease, including pre-surgical comorbidities, postoperative complications, extent of tumor, and recurrence. Golden-angle radial sparse parallel (GRASP) magnetic resonance images were obtained from a subset of SCAs and NFAs. Permeability data were obtained to compare signal-to-time curve variation between the 2 groups.

RESULTS

With multivariate regression analysis, SCAs showed higher rates of hemorrhage on preoperative imaging than NFAs (P = 0.017). SCAs presented more frequently with headache (P = 0.012), vision changes (P = 0.041), and fatigue (P = 0.028). SCAs exhibited greater extent of tumor burden with increased occurrence of stalk deviation (P = 0.008), suprasellar invasion (P = 0.021), optic chiasm compression (P = 0.022), and cavernous sinus invasion (P = 0.015). On GRASP imaging, SCAs had significantly lower permeability of contrast than NFAs (P = 0.001). Thirty percent of SCAs were noted to recur with a 14% recurrence rate in other NFAs, though this difference was not of statistical significance (P = 0.220).

CONCLUSIONS

SCAs exhibit features of more aggressive disease. Interestingly, a significant increase in recurrence was not seen despite these features. The results of this study support the growing body of evidence that SCAs behave more aggressively than other NFPAs and was able to provide some insight into factors that may contribute to recurrence.

Silent Corticotroph Tumor with Adrenocortical Choristoma in an Eleven-year-old Boy

Silent corticotroph tumors are composed of corticotroph cells, but do not manifest any biochemical or clinical evidence of hypercortisolism. A choristoma is a benign, congenital proliferation of histologically mature tissue elements normally not present at the site of occurrence. The existence of adrenocortical cells within the pituitary gland, which can be explained as a choristoma, is a very rare entity, and the co-occurrence of these two entities have only been reported in few cases. We report an 11-year-old boy with central hypothyroidism. On cranial magnetic resonance imaging a pituitary tumor was detected, and histopathological studies led to a diagnosis of an adrenal choristoma and a silent corticotroph tumor in the pituitary gland. The presence of adrenocortical cells were confirmed by positive calretinin, inhibin and Melan A staining, and the corticotroph cells by immunohistochemistry demonstrating adrenocorticotropic hormone positivity. Herein, we report the fourth and the youngest case of silent corticotroph tumor with adrenocortical choristoma in the literature. Even though the underlying mechanism is not fully understood, suggested mechanisms are discussed.

Case Report: Progression of a Silent Corticotroph Tumor to an Aggressive Secreting Corticotroph Tumor, Treated by Temozolomide. Changes in the Clinic, the Pathology, and the β-Catenin and α-SMA Expression

Clinically silent corticotroph tumors are usually macroadenomas that comprise 20% of ACTH tumors. They frequently progress to aggressive tumors with high recurrence, invasiveness, and on rare occasions, they may become hormonally active causing Cushing's disease. Trustable biomarkers that can predict their aggressive course, as well as their response to traditional or new therapies, are paramount. Aberrant β-Catenin expression and localization have been proposed as responsible for several malignancies including pituitary tumors. Nevertheless, the role of β-Catenin in the aggressive transformation of silent corticotropinomas and their response to Temozolomide salvage treatment have not been explored yet. In this work, we present a case of a silent corticotroph tumor that invaded cavernous sinus and compressed optic chiasm and, after a first total resection and tumor remission it recurred six years later as an aggressive ACTH-secreting tumor. This lesion grew with carotid compromise and caused Cushing's signs. It required multiple medical treatments including Cabergoline, Ketoconazole, TMZ, and radiotherapy. Besides, other two surgeries were needed until it could be controlled. Interestingly, we found α-SMA vascular area reduction and differential β-Catenin cell localization in the more aggressive tumor stages characterized by high Ki-67 indexes and p53 expression. Our results may indicate a role of angiogenesis and β-Catenin trigged events in the pituitary tumor progression, which could in turn affect the response to TMZ and/or conventional treatments. These molecular findings in this unusual case could be useful for future management of aggressive pituitary tumors.

An Update on Silent Corticotroph Adenomas: Diagnosis, Mechanisms, Clinical Features, and Management

Simple Summary

The 2017 World Health Organization classification of endocrine tumors defines pituitary adenomas based on their cell lineages. T-PIT can serve as a complimentary tool for further identification of silent corticotroph adenomas (SCAs). Unlike functioning corticotroph adenomas in patients with Cushing’s disease, SCAs present no clinical and biochemical features of Cushing’s syndrome. SCAs have been shown to exhibit a more aggressive course characterized by a higher probability of recurrence and resistance to conventional treatment due to their intrinsic histological features. The aim of our review is to offer an update on the diagnosis, mechanisms, clinical features and management of SCAs. Studies of the molecular mechanisms of SCA pathogenesis will provide new directions for the diagnosis and management of SCAs.

Abstract

With the introduction of 2017 World Health Organization (WHO) classification of endocrine tumors, T-PIT can serve as a complementary tool for identification of silent corticotroph adenomas (SCAs) in some cases if the tumor is not classifiable by pituitary hormone expression in pathological tissue samples. An increase of the proportion of SCAs among the non-functioning pituitary adenomas (NFPAs) has been witnessed under the new rule with the detection of T-PIT-positive ACTH-negative SCAs. Studies of molecular mechanisms related to SCA pathogenesis will provide new directions for the diagnosis and management of SCAs. A precise pathological diagnosis can help clinicians better identify SCAs. Understanding clinical features in the context of the pathophysiology of SCAs is critical for optimal management. It could provide information on appropriate follow-up time and aid in early recognition and treatment of potentially aggressive forms. Management approaches include surgical, radiation, and/or medical therapies.

Silent corticotroph pituitary adenomas: clinical characteristics, long-term outcomes, and management of disease recurrence

OBJECTIVE

Silent corticotroph adenomas (SCAs) are a distinct subtype of nonfunctioning pituitary adenomas (NFAs) that demonstrate positive immunohistochemistry for adrenocorticotropic hormone (ACTH) without causing Cushing's disease. SCAs are hypothesized to exhibit more aggressive behavior than standard NFAs. The authors analyzed their institution's surgical experience with SCAs in an effort to characterize rates of invasion, postoperative clinical outcomes, and patterns of disease recurrence and progression. The secondary objectives were to define the best treatment strategies in the event of tumor recurrence and progression.

METHODS

A retrospective analysis of patients treated at the authors' institution identified 100 patients with SCAs and 841 patients with NFAs of other subtypes who were treated surgically from 2000 to 2019. Patient demographics, tumor characteristics, surgical and neuroimaging data, rates of endocrinopathy, and neurological outcomes were recorded. Cohorts of patients with SCAs and patients with standard NFAs were compared with regard to these characteristics and outcomes.

RESULTS

The SCA cohort presented with cranial neuropathy (13% vs 5.7%, p = 0.0051) and headache (53% vs 42.3%, p = 0.042) compared to the NFA cohort, despite similar rates of apoplexy. The SCA cohort included a higher proportion of women (SCA 60% vs NFA 45.8%, p = 0.0071) and younger age at presentation (SCA 50.5 ± 13.3 vs NFA 54.6 ± 14.9 years of age, p = 0.0082). Reoperations were comparable between the cohorts (SCA 16% vs NFA 15.7%, p = 0.98). Preoperative pituitary function was comparable between the cohorts with the exception of higher rates of preoperative panhypopituitarism in NFA patients (2% vs 6.1%, respectively; p = 0.0033). The mean tumor diameter in SCA patients was 24 ± 10.8 mm compared to 26 ± 11.3 mm in NFA patients (p = 0.05). Rates of cavernous sinus invasion were higher in the SCA group (56% vs 49.7%), although this result did not reach statistical significance. There were no significant differences in extent of resection, intraoperative CSF leak rates, endocrine or neurological outcomes, or postoperative complications. Ki-67 rates were significantly increased in the SCA cohort (2.88 ± 2.79) compared to the NFA cohort (1.94 ± 1.99) (p = 0.015). Although no differences in overall rates of progression or recurrence were noted, SCAs had a significantly lower progression-free survival (24.5 vs 51.1 months, p = 0.0011). Among the SCA cohort, progression was noted despite the use of adjuvant radiosurgery in 33% (n = 4/12) of treated tumors. Adequate tumor control was not achieved in half (n = 6) of the SCA progression cohort despite radiosurgery or multiple resections.

CONCLUSIONS

In this study, to the authors' knowledge the largest surgical series to assess outcomes in SCAs to date, the findings suggest that SCAs are more biologically aggressive tumors than standard NFAs. The progression-free survival duration of patients with SCAs is only about half that of patients with other NFAs. Therefore, close neuroimaging and clinical follow-up are warranted in patients with SCAs, and residual disease should be considered for early postoperative adjuvant radiosurgery, particularly in younger patients.

Radiomics analysis allows for precise prediction of silent corticotroph adenoma among non-functioning pituitary adenomas

OBJECTIVE

To predict silent corticotroph adenomas (SCAs) among non-functioning pituitary adenomas preoperatively using noninvasive radiomics.

METHODS

A total of 302 patients including 146 patients diagnosed with SCAs and 156 patients with non-SCAs were enrolled (training set: n = 242; test set: n = 60). Tumor segmentation was manually generated using ITK-SNAP. From T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), and contrast-enhanced T1WI, 2550 radiomics features were extracted using Pyradiomics. Pearson's correlation coefficient values were calculated to exclude redundant features. Several machine learning algorithms were developed to predict SCAs incorporating the radiomics and semantic features including clinical, laboratory, and radiology-associated features. The performance of models was evaluated by AUC.

RESULTS

Patients in the SCA group were younger (49.5 vs 55.2 years old) and more female (85.6% vs 37.2%) than those in the non-SCA group (p < 0.001). More invasiveness (p = 0.011) and cystic and microcystic change (p < 0.001) were observed in patients with SCAs. The ensemble algorithm presented the largest AUC of 0.927 among all the algorithms trained in the test set, and the accuracy, specificity, and sensitivity of predicting SCAs were all 0.867 (at cut-off 0.5). The overall model performed better than that only using semantic features available in the clinic. Radiomics prediction was the most important feature, with gender ranking second and age ranking third. Radiomics features on T2WI were superior to those on other MR modalities in SCA prediction.

CONCLUSION

Our ensemble learning model outperformed current clinical practice in differentiating patients with SCAs and non-SCAs using radiomics, which might help make appropriate treatment strategies.

KEY POINTS

• Radiomics might improve the preoperative diagnosis of SCAs by MR images. • T2WI was superior to T1WI and CE-T1WI in the preoperative diagnosis of SCAs. • The ensemble machine learning model outperformed current clinical practice in SCAs diagnosis and treatment decision-making could be more individualised using the nomogram.

Spontaneous remission of Cushing's disease: A systematic review

Spontaneous remission is rare in Cushing's disease. We describe one illustrative case and provide a systematic review of cases previously reported in the literature. Case report: A 51-year-old woman diagnosed with Cushing's disease underwent 9 months' isolated metyrapone treatment. Two months after end of treatment, she was admitted with acute kidney failure. After another 4 months, in June 2020, there was no evidence of hypercortisolism, either clinically or biochemically, or of hypocortisolism. At the time of writing, 1 year later, she was still in remission. Cases reported in the literature: 23 patients were reported, including the present case. 87% were female with a median age of 32 years. Ten of those with radiologically visible tumors had microadenoma (44%) and 7 had macroadenoma (30%). Mean time from diagnosis to spontaneous remission was 5 months, and was shorter in macroadenoma (1 month) than in microadenoma (13.5 months). Treatments before spontaneous remission were: no treatment (65%), steroidogenesis enzyme inhibitors (22%), bilateral adrenalectomy and adrenal autotransplantation (5%), partial bilateral adrenalectomy (4%), and incomplete pituitary surgery (4%). Pituitary tumor apoplexy was the most frequently incriminated event (91%), radiologically documented in 43% of patients. Mean remission during follow-up was 28 months (range, 6-130 months). Recurrence occurred in 39% (n=9) of patients. Although several mechanisms responsible for this phenomenon have been proposed, clinical or subclinical pituitary tumor apoplexy, the latter sometimes presenting atypically, seems to be the most frequently incriminated event. Doctors should be aware of this, and regular follow-up is mandatory due to its unpredictability.

Clinical profiles of silent corticotroph adenomas compared with silent gonadotroph adenomas after adopting the 2017 WHO pituitary classification system

PURPOSE

Silent corticotroph adenomas (SCAs) can be redefined according to the 2017 World Health Organization pituitary classification system with the introduction of T‑PIT, a transcription factor. We studied the clinical features of these redefined SCAs.

METHODS

We compared 112 patients with SCAs and 198 patients with silent gonadotroph adenomas (SGAs) who underwent surgery from January 2019 to May 2020.

RESULTS

The prevalence of SCAs increased from 21.3 to 30.2% under the new classification rules. T-PIT-positive, adrenocorticotropic hormone-negative SCAs and T-PIT-positive, adrenocorticotropic hormone-positive SCAs exhibited similar clinical features. SCAs exhibited significant female preponderance (90.2% vs. 29.8%, P < 0.0001); more frequent invasion (36.6% vs. 7.6%, P < 0.0001), especially multiple-site invasion (P < 0.0001); and marked cystic changes on imaging compared with SGAs (54.5% vs. 19.2%, P < 0.0001). SCAs had a softer tumor consistency (89.2% vs. 61.1%, P < 0.0001). Gross total resection was achieved in 66.1% of SCAs and 66.2% of SGAs (P > 0.9999). The overall recurrence/progression rates of SCAs and SGAs were 9.8% and 6.6% at 14.1 and 13.5 months of follow-up, respectively (P = 0.3765). The proportion of patients with more than two recurrences requiring multiple surgeries and radiation was similar between SCAs and SGAs (7.1% vs. 3.0%, P = 0.1514). However, multiple recurrences of SCAs affected younger patients than SGAs (39.0 vs. 53.5 years, P = 0.0433).

CONCLUSIONS

The prevalence of SCAs increased with the introduction of T-PIT. SCAs and SGAs exhibited comparable size and recurrence/progression rates, but SCAs showed increased invasion and more marked cystic change. Aggressive SCAs tended to affect younger patients. Close long-term monitoring for SCA recurrence/progression is required.

The silent variants of pituitary tumors: demographic, radiological and molecular characteristics

INTRODUCTION

Tumors of the anterior pituitary gland (PTs) are mostly benign tumors with a low prevalence, which has nevertheless increased with advances in brain radiology techniques. Nearly half of PTs are not associated with a clinical endocrine syndrome. These tumors have been indistinctly named non-functioning pituitary adenomas (NFPAs) or silent pituitary tumors (SPTs) and the mechanisms of silencing are not fully known.

AIM

To study the frequency and characterize the silent variant of PTs in a large local series, and to assess their pituitary adenohypophyseal gene expression.

METHODS

This observational, cross-sectional study was performed in a Pituitary Tumor Center of Excellence and involved 268 PTs. After identifying the different subtypes according to the immunohistochemical (IHC) expression of adenohypophyseal hormones, we studied their gene expression by RT-qPCR.

RESULTS

We found that silent tumors were larger and more invasive, but not more proliferative than their functional counterparts. The RT-qPCR complements the IHC typification of PTs, reducing the proportion of null-cell subtype. Finally, some silent PT subtype variants showed lower specific adenohypophyseal hormone gene expression than their functional counterparts, which may contribute to the absence of endocrine manifestations.

CONCLUSIONS

This paper highlights the importance of identifying the silent variant of the PTs subtypes. As expected, silent tumors were larger and more invasive than their functioning counterparts. However, there was no difference in the proliferation activity between them. Finally, the lower specific gene expression in the silent than in the functioning counterparts of some PTs subtypes gives insights into the silencing mechanisms of PTs.

DNA damage and growth hormone hypersecretion in pituitary somatotroph adenomas

Drivers of sporadic benign pituitary adenoma growth are largely unknown. Whole-exome sequencing of 159 prospectively resected pituitary adenomas showed that somatic copy number alteration (SCNA) rather than mutation is a hallmark of hormone-secreting adenomas and that SCNAs correlate with adenoma phenotype. Using single-gene SCNA pathway analysis, we observed that both cAMP and Fanconi anemia DNA damage repair pathways were affected by SCNAs in growth hormone-secreting (GH-secreting) somatotroph adenomas. As somatotroph differentiation and GH secretion are dependent on cAMP activation and we previously showed DNA damage, aneuploidy, and senescence in somatotroph adenomas, we studied links between cAMP signaling and DNA damage. Stimulation of cAMP in C57BL/6 mouse primary pituitary cultures using forskolin or a long-acting GH-releasing hormone (GHRH) analog increased GH production and DNA damage measured by H2AX phosphorylation and a comet assay. Octreotide, a somatostatin receptor ligand that targets somatotroph adenoma GH secretion in patients with acromegaly, inhibited cAMP and GH and reversed DNA damage induction. In vivo long-acting GHRH treatment also induced pituitary DNA damage in mice. We conclude that cAMP, which induces somatotroph proliferation and GH secretion, may concomitantly induce DNA damage, potentially linking hormone hypersecretion to SCNA and genome instability. These results elucidating somatotroph adenoma pathophysiology identify pathways for targeted treatment.

Aggressive Cushing's Disease: Molecular Pathology and Its Therapeutic Approach

Cushing's disease is a syndromic pathological condition caused by adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (ACTHomas) mediated by hypercortisolemia. It may have a severe clinical course, including infection, psychiatric disorders, hypercoagulability, and metabolic abnormalities, despite the generally small, nonaggressive nature of the tumors. Up to 20% of ACTHomas show aggressive behavior, which is related to poor surgical outcomes, postsurgical recurrence, serious clinical course, and high mortality. Although several gene variants have been identified in both germline and somatic changes in Cushing's disease, the pathophysiology of aggressive ACTHomas is poorly understood. In this review, we focused on the aggressiveness of ACTHomas, its pathology, the current status of medical therapy, and future prospects. Crooke's cell adenoma (CCA), Nelson syndrome, and corticotroph pituitary carcinoma are representative refractory pituitary tumors that secrete superphysiological ACTH. Although clinically asymptomatic, silent corticotroph adenoma is an aggressive ACTH-producing pituitary adenoma. In this review, we summarize the current understanding of the pathophysiology of aggressive ACTHomas, including these tumors, from a molecular point of view based on genetic, pathological, and experimental evidence. The treatment of aggressive ACTHomas is clinically challenging and usually resistant to standard treatment, including surgery, radiotherapy, and established medical therapy (e.g., pasireotide and cabergoline). Temozolomide is the most prescribed pharmaceutical treatment for these tumors. Reports have shown that several treatments for patients with refractory ACTHomas include chemotherapy, such as cyclohexyl-chloroethyl-nitrosourea combined with 5-fluorouracil, or targeted therapies against several molecules including vascular endothelial growth factor receptor, cytotoxic T lymphocyte antigen 4, programmed cell death protein 1 (PD-1), and ligand for PD-1. Genetic and experimental evidence indicates that some possible therapeutic candidates are expected, such as epidermal growth factor receptor tyrosine kinase inhibitor, cyclin-dependent kinase inhibitor, and BRAF inhibitor. The development of novel treatment options for aggressive ACTHomas is an emerging task.

Recent Understanding and Future Directions of Recurrent Corticotroph Tumors

Corticotroph tumors (CTs) are pituitary neoplasms arising from the Tpit lineage, which may or not express adrenocorticotrophic hormone (ACTH). Functioning CTs cause Cushing's disease (CD), which has high morbidity and mortality due to hypercortisolemia. "Non-functioning" or silent CTs (SCT) and the Crooke's cell subtypes do not cause CD and may be asymptomatic until manifested by compressive symptoms and are more frequently found as macroadenoma. Both tend toward more aggressive behavior, recurrence, and a higher rate of malignant transformation to pituitary carcinoma. Tumorigenesis involves genetic, epigenetic, and post-transcriptional disruption of cell-cycle regulators, which increase cell proliferation, POMC overexpression, ACTH transcription, and/or hypersecretion. Furthermore, functioning CTs develop resistance to glucocorticoid-mediated negative feedback on ACTH secretion, through increased expression of testicular orphan nuclear receptor 4 (TR4), heat-shock protein 90 (HSP90), and loss-of-function mutation of CDK5 and ABL enzyme substrate 1 (CABLES1) gene. Overt autonomous hypercortisolemia is difficult to control, and multiple diagnostic studies and therapeutic modalities are commonly required. Cell-cycle regulation depends mainly on p27, cyclin E, cyclin-dependent kinases (CDKs), and the retinoblastoma protein (Rb)/E2F1 transcription factor complex. Gain-of-function mutations of ubiquitin-specific protease (USP) 8, USP48, and BRAF genes may subsequently cause overexpression of epithelial growth factor receptor (EGFR), and enhance POMC transcription, cell proliferation, and tumor growth. Epigenetic changes through micro RNAs and decreased DNA deacetylation by histone deacetylase type 2 (HDAC2), may also affect tumor growth. All the former mechanisms may become interesting therapeutic targets for CTs, aside from temozolomide, currently used for aggressive tumors. Potential therapeutic agents are EGFR inhibitors such as gefitinib and lapatinib, the purine analog R-roscovitine by dissociation of CDK2/Cyclin E complex, the HSP90 inhibitor silibinin (novobiocin), to reduce resistance to glucocorticoid-mediated negative feedback, and BRAF inhibitors vemurafenib and dabrafenib in BRAF V600E positive tumors. This review summarizes the molecular mechanisms related to CTs tumorigenesis, their diagnostic approach, and provides an update of the potential novel therapies, from the lab bench to the clinical translation.

Nelson Syndrome: Clival Invasion of Corticotroph Pituitary Adenoma Resulting in Alternating Sixth Nerve Palsies

ABSTRACT

A 44-year-old woman presented with 2 painful and self-limited episodes of binocular horizontal diplopia within 1 year that at the beginning were thought to be secondary to microvascular insult. Her medical history was significant for Cushing syndrome status post transsphenoidal resection with bilateral adrenalectomy 4 years prior, hypertension, and diabetes mellitus. Neuro-ophthalmic evaluation was significant for left abduction deficit and incomitant esotropia consistent with left abducens nerve palsy. Of note, the patient had experienced a similar episode but on the contralateral side a few months prior. Although initially MRI of the brain demonstrated stable residual postoperative finding in the sella, upon review, an heterogenous T-1 hypointense marrow in the clivus was noted. Hypermetabolism of the clivus was also noted on computed tomography positron emission tomography of the skull base. A clival biopsy demonstrated a corticotroph adenoma with elevated proliferation index and scattered mitoses. A corticotroph pituitary adenoma after adrenalectomy, also known as Nelson syndrome, was diagnosed. Radiation therapy was offered to the patient, and resolution of symptoms was gradually observed.

RECURRENT PITUITARY APOPLEXY IN AN ADENOMA WITH SWITCHING PHENOTYPES

Objective

To describe an unusual presentation of a patient with recurrent pituitary apoplexy of an adenoma that switched phenotypes from a nonfunctioning, or silent gonadotroph adenoma (SGA), to a silent corticotroph adenoma (SCA). We discuss the potential etiologies of both recurrent pituitary apoplexy and phenotype switching of pituitary tumors.

Methods

The presented case includes clinical and biochemical findings, surgical outcomes, and pathologic reports related to the treatment of our patient who presented with recurrent pituitary apoplexy.

Results

A 56-year-old man presented for evaluation of decreased libido and was found to have a low testosterone level. A pituitary magnetic resonance image demonstrated an 8-mm pituitary adenoma. He underwent transsphenoidal surgery (TSS) to remove the tumor and pathology demonstrated an SGA immunopositive for luteinizing hormone and follicle-stimulating hormone with evidence of apoplexy. Eight years later, the patient underwent another TSS after developing acute-onset headache, vomiting, and a cranial nerve palsy. Pathology at this time showed a necrotic tumor consistent with apoplexy with negative immunostains for all pituitary tumors. Three years after this, the tumor recurred and after another TSS the tumor stained positive for adrenocorticotropic hormone but was negative for luteinizing hormone and follicle-stimulating hormone with hemorrhage consistent with apoplexy. A few years afterward, he again developed acute-onset headache and cranial nerve palsies and had another TSS. On pathology, the tumor demonstrated extensive necrosis consistent with apoplexy and again stained positive for adrenocorticotropic hormone. The patient was then referred for radiation therapy and was subsequently lost to follow up.

Conclusion

Recurrent pituitary apoplexy in the same patient has only been described 3 times in the literature. There have been no case reports of a pituitary adenoma that switched phenotypes from an SGA to SCA. We suggest that pituitary apoplexy may recur multiple times due to a tumor with particularly fragile vessel walls and increased vascularization. We review the literature that suggests clinical and molecular similarities between SGAs and SCAs. Further studies are needed to determine the etiologies of recurrent apoplexy and pituitary adenomas with switching phenotypes.

Preoperative vascular heterogeneity and aggressiveness assessment of pituitary macroadenoma based on dynamic contrast-enhanced MRI texture analysis

PURPOSE

To assess the vascular heterogeneity and aggressiveness of pituitary macroadenomas (PM) using texture analysis based on Dynamic Contrast-Enhanced MRI (DCE-MRI).

METHOD

Fifty patients with pathologically confirmed PM, including 32 patients with aggressive PM (aggressive group) and 18 patients with non-aggressive PM (non-aggressive group), were included in this study. The preoperative DCE-MRI and clinical data were collected from all patients. The features based on Ktrans, Ve, and Kep were generated using Omni-Kinetics software. Independent-samples t-test and Mann-Whitney U test were used for comparison between two groups. Logistic regression analysis was used to determine the optimal model for distinguishing aggressive and non-aggressive PM.

RESULTS

Six features related to tumor morphology, 24 features in Ktrans, 20 features in Ve, and 3 features in Kep were significantly different between the aggressive and non-aggressive groups. Volume count, gray-level non-uniformity in Ktrans, voxel value sum in Ve and run-length non-uniformity in Kep (AUC = 0.816, 0.903, 0.785, 0.813) were considered the best feature for tumor diagnosis. After modeling, the diagnosis efficiency of mean model and total model was desirable (AUC = 0.859 and 0.957), and the diagnostic efficiency of morphological, Ktrans, Ve and Kep features model was improved (AUC = 0.845, 0.951, 0.847, 0.804).

CONCLUSIONS

Texture analysis based on DCE-MRI elucidates the vascular heterogeneity and aggressiveness of pituitary adenoma. The total model could be used as a new noninvasive method for predicting the aggressiveness of pituitary macroadenoma.

Pituitary Adenomas with Changing Phenotype: A Systematic Review

PURPOSE AND METHODS

Phenotype transformation in pituitary adenomas (PA) is a little known and unexpected clinical phenomenon. We describe two illustrative cases and performed a systematic review of cases reported in literature.

RESULTS

Case 1: A 24-year-old woman underwent surgery because of Cushing's disease. A complete tumor resection and hypercortisolism resolution was achieved. Two years later, tumor recurred but clinical and hormonal hypercortisolism were absent. Case 2: A 77-year-old woman underwent surgery due to acromegaly. A complete tumor resection and GH excess remission was achieved. Four years later, tumor recurred but clinical and hormonal acromegaly was ruled out. Search of literature: From 20 patients (including our cases), 75% were female with median age 45 (19) years. Ten patients (50%) had initially functioning PA: 8 switched to NFPA (5 ACTH-secreting PA, 2 prolactinomas and 1 acromegaly) and 2 exchanged to acromegaly from TSH-secreting PA and microprolactinoma. One patient developed a pituitary carcinoma from ACTH-secreting PA. Ten patients (50%) initially had NFPA; 9 developed Cushing's disease (4 silent corticotroph adenomas, 4 null cell PA and 1 managed conservatively). One patient with silent somatotroph PA changed to acromegaly. Treatments before transformation were surgery (80%), radiotherapy (40%), pharmacological (40%) and in 2 patients switching happened without any treatment. Median follow-up until transformation was 72 months (range 12-276).

CONCLUSION

PA can change from functioning to (NF) non-functioning (vice versa) and even exchange their hormonal expression. Clinicians should be aware and a careful lifelong follow-up is mandatory to detect it.

A machine learning model to precisely immunohistochemically classify pituitary adenoma subtypes with radiomics based on preoperative magnetic resonance imaging

PURPOSE

The type of pituitary adenoma (PA) cannot be clearly recognized with preoperative magnetic resonance imaging (MRI) but can be classified with immunohistochemical staining after surgery. In this study, a model to precisely immunohistochemically classify the PA subtypes by radiomic features based on preoperative MR images was developed.

METHODS

Two hundred thirty-five pathologically diagnosed PAs, including t-box pituitary transcription factor (Tpit) family tumors (n = 55), pituitary transcription factor 1 (Pit-1) family tumors (n = 110), and steroidogenic factor 1 (SF-1) family tumors (n = 70), were retrospectively studied. T1-weighted, T2-weighted and contrast-enhanced T1-weighted images were obtained from all patients. Through imaging acquisition, feature extraction and radiomic data processing, 18 radiomic features were used to train support vector machine (SVM), k-nearest neighbors (KNN) and Naïve Bayes (NBs) models. Ten-fold cross-validation was applied to evaluate the performance of these models.

RESULTS

The SVM model showed high performance (balanced accuracy 0.89, AUC 0.9549) whereas the KNN (balanced accuracy 0.83, AUC 0.9266) and NBs (balanced accuracy 0.80, AUC 0.9324) models displayed low performance based on the T2-weighted images. The performance of the T2-weighted images was better than that of the other two MR sequences. Additionally, significant sensitivity (P = 0.031) and specificity (P = 0.012) differences were observed when classifying the PA subtypes by T2-weighted images.

CONCLUSIONS

The SVM model was superior to the KNN and NBs models and can potentially precisely immunohistochemically classify PA subtypes with an MR-based radiomic analysis. The developed model exhibited good performance using T2-weighted images and might offer potential guidance to neurosurgeons in clinical decision-making before surgery.

Accuracy of microcystic aspect on T2-weighted MRI for the diagnosis of silent corticotroph adenomas

INTRODUCTION

A single study suggested that silent corticotropinomas (SCAs) have a different imaging phenotype, with microcystic aspect on T2-weighted sequence of magnetic resonance imaging (T2-MRI). This study only analysed manifest and silent corticotropinomas and nonfunctioning gonadotroph adenomas. Therefore, the prevalence of microcystic patterns of other tumours is not known.

AIM

To analyse frequency of microcystic patterns on T2-MRI in all subtypes of pituitary adenomas and determine accuracy of this radiological finding for diagnosing SCA.

METHODS

Consecutive pituitary adenoma patients who underwent surgery between 2013 and 2016 at a single centre were included. T2-MRIs were evaluated by a radiologist and an endocrinologist blinded to histological diagnosis.

RESULTS

A total of 143 patients (52% female) with median age of 49 years (14-80) were included. Clinically, there were 90 nonfunctioning pituitary adenomas (NFPAs), 32 somatotropinomas, 13 corticotropinomas, five prolactinomas and three TSH-secreting adenomas. Of the patients with NFPA, 12 (13%) were SCAs, 73 (79%) were gonadotropinomas and five (6%) were positive for prolactin (three) or TSH (two). A microcystic pattern was observed in 16 tumours (11%): one somatotropinoma, one corticotropinoma, seven SCAs and seven gonadotropinomas, and in no prolactinomas or TSH-secreting adenomas. It was more common in SCAs than in other tumours (58.3% vs 6.9%, respectively, P < .001) and had a sensitivity of 58%, a specificity of 93% and an accuracy of 90% to define an SCA.

CONCLUSION

Microcystic aspect on T2-MRI is able to define SCA with a good accuracy and can be a useful tool, considering the more aggressive behaviour of these tumours.

Clinical, Laboratory, and Treatment Profiles of Silent Corticotroph Adenomas That Have Transformed to the Functional Type: A Case Series With a Literature Review

Purpose: Silent corticotroph adenoma (SCA) is clinically non-functional pituitary adenoma with expression of corticotropin or Tpit. To further understand the characteristics of this rare type of SCA transforming to a functional SCA, we retrospectively reviewed SCAs that converted to typical Cushing's syndrome at a tertiary medical center and the relevant literature. Methods: Patients were identified based on the diagnosis of pituitary adenoma without symptoms of hypercortisolism at the initial visit with positive Immunohistochemical (IHC) staining for corticotropin or Tpit after surgery and subsequent transformation to functional SCAs during the follow-up period from March 1990 to January 2020 at Peking Union Medical College Hospital and in the literature. The characteristics of the clinical manifestations, biochemical results, imaging findings, pathology findings and outcome were analyzed. Results: Altogether, 16 patients were included in the study with an average age of 42.0 ± 12.48 (18-65) years at the first visit. Females were slightly predominant (F:M = 1.3:1). The median time of conversion from the nonfunctional to the functional type was 30 (13.0, 68.3) months. Once a functional SCA developed, the adrenocorticotropic hormone (ACTH) level and 24-h urine free cortisol were increased 3.8- (2.6, 12.9) and 5.3- (2.6, 19.3) fold, respectively, above the normal range. Approximately 50% of the patients had macrocystic changes on pituitary MRI. All 16 patients experienced 1-5 surgeries with a median of 2.5 (2.0, 4.0) surgeries. The proportion of patients with Ki-67 ≥ 3% increased from 22.2% (2/9) at the beginning to 50% (7/14) at the time of functional SCA diagnosis. Thirteen patients received radiotherapy, and 4 patients (30.8%) achieved remission. Four patients with refractory functional SCAs received temozolomide treatment with the normalization of cortisol in 4 cases and reduced tumor volume in 3 cases. Conclusion: In this study, all cases that transformed to functional SCAs were macroadenomas. Hypercortisolism was more severe in functional SCA patients. The tumors tended to have frequent recurrence and were highly invasive. Temozolomide could be a promising treatment for refractory functional SCA cases. Long-term follow-up is needed for nonfunctional SCAs since some cases have the potential to transform to clinical Cushing's syndrome.

Metabolic profiling reveals distinct metabolic alterations in different subtypes of pituitary adenomas and confers therapeutic targets

BACKGROUND

Pituitary adenomas are common brain tumors. Although transsphenoidal surgery are able to achieve extensive tumor removal, the rate of recurrence ranges from 5 to 20% depending on the different subtype. Further understanding of these tumors is needed to develop novel strategies to improve the prognosis of patients. But their metabolic characteristics are largely unknown.

METHODS

We used metabolomic, transcriptomic, and proteomic approaches to systematically investigate eight subtypes of pituitary adenomas and normal pituitary glands. By blocking IDH2, we investigate IDH2 play an inhibitory role in GH tumor cell growth and tumor secretion.

RESULTS

We found that all of the pituitary adenomas displayed downregulated glucose metabolism and glycolysis compared to normal tissues. Together with the differences in amino acids and fatty acids, we categorized these tumors into three clusters. We then re-established the reprogrammed metabolic flux in pituitary adenomas based on multiomic analyses. Take growth hormone-secreting pituitary adenomas as an example, we revealed that IDH2 is a key player in the reprogrammed metabolism of such tumors. By blocking IDH2, we confirmed that IDH2 is a potential target for the inhibition of tumor cell growth and tumor secretion.

CONCLUSIONS

Our study first uncovered the metabolic landscape of pituitary adenomas and demonstrated a possible way to inhibit tumor growth by regulating aberrant metabolism.

Invited Review: Pathology of pituitary neuroendocrine tumours: present status, modern diagnostic approach, controversies and future perspectives from a neuropathological and clinical standpoint

Neuroendocrine tumours of the adenohypophysis have traditionally been designated as pituitary adenomas to underline their usually indolent growth and lack of metastatic potential. However, they may demonstrate a huge spectrum of growth patterns and endocrine disturbances, some of them significantly affecting health and quality of life. To predict tumour growth, risk of postoperative recurrence and response to medical therapy in patients with pituitary neuroendocrine tumours is challenging. A thorough histopathological and immunohistochemical diagnostic work-up is an obligatory part of a multidisciplinary effort to precisely define the tumour type and assess prognostic and predictive factors on an individual basis. In this review, we have summarized the current status in the pathology in pituitary neuroendocrine tumours based on the selection of references from the PubMed database. We have presented possible diagnostic approaches according to the current pituitary cell lineage-based classification. The importance of recognizing histological subtypes with potentially aggressive behaviour and identification of prognostic and predictive tissue biomarkers have been highlighted. Controversies related to particular subtypes of pituitary tumours and a still limited prognostic impact of the current classification indicate the need for further refinement. Multidisciplinary approach including clinical, pathological and molecular genetic characterization will be essential for improved personalized therapy and the search for novel therapeutic targets in patients with pituitary neuroendocrine tumours.

Ki-67 labeling index and expression of p53 are non-predictive for invasiveness and tumor size in functional and nonfunctional pituitary adenomas

BACKGROUND

It is still controversial whether an increased proliferation index is correlated with the tumor invasiveness of pituitary adenomas. A homogeneous large monocentric series of pituitary adenomas was retrospectively analyzed. The correlation between the proliferation indices (Ki-67 and p53 expression levels) and invasiveness and size of pituitary adenomas was investigated in primary operated and recurrent adenomas.

METHOD

Four hundred thirty-nine patients after resection of pituitary adenomas were retrospectively included (43 recurrent tumors, 196 null cell adenomas, 86 somatotroph adenomas, 55 corticotroph adenomas, 55 prolactinomas, 4 thyreotroph adenomas). The maximum tumor diameter and tumor invasiveness in Knosp grading were assessed and Ki-67 and p53 immunostaining was performed. The role of invasiveness was evaluated using a cumulative odds ordinal logistic regression. For calculating the effect of tumor size, a one-way analysis of variance (ANOVA) was conducted.

RESULTS

Overall and in the subgroups, no significant correlation between proliferation indices and mean tumor diameter was found. No significant predictive expression value of Ki-67 and p53 on tumor invasiveness and in recurrent tumors could be demonstrated. There was a tendency that Ki-67 LI and p53 LI are higher in recurrent corticotroph adenomas and lactotroph adenomas but values did not reach the significant level.

CONCLUSION

Invasive character of pituitary adenomas is neither correlated with increased Ki-67 LI nor with increased p53 expression. Proliferation parameters are independent from adenoma size at initial presentation. The partly elevated expression of Ki-67 in recurrent tumors underlines the clinical importance of the marker.

[Morphofunctional features of non-functioning pituitary adenomas]

Non-functioning pituitary adenomas (NFPAs) account for about 30% of all pituitary tumors. NFPAs are characterized by the lack of secretory potential or its weak expression insufficient for determination of the blood level of adenohypophyseal tropic hormones and for development of a specific clinical picture. Morphologically, NFPAs are a heterogeneous group of tumors, the classification of which was previously based only on immunoreactivity for pituitary tropic hormones. The WHO revised its Classification of Tumors of Endocrine Organs (4th edition) in 2017. The main changes relate to adenohypophysial-cell lineage for the designation of adenomas into subtypes. The introduction of transcription factor antibodies has become a fundamentally new approach to the classification of NFPAs, which is necessary to recognize less differentiated tumor types. This paper provides information on the new histopathological classification of pituitary adenomas, on the theories of silent adenomas, and on the proliferative and prognostic markers of NFPAs.

Aggressive and malignant pituitary tumours: state-of-the-art

Pituitary adenomas are unique in multiple ways. They are rarely malignant in terms of metastases; yet, they may be aggressive. Their cancerous potential is defined in a classic oncological way by the ability to metastasise, and therefore, it has been crucial to differentiate this process from aggressive behaviour, characterised as a particularly invasive and/or recurrent behaviour and resistance to common modalities of therapy. Recently, however, important changes have been introduced to the diagnosis and management of aggressive and malignant pituitary tumours including the 4th edition of the World Health Organization (WHO) classification for endocrine tumours (2017) as well as ESE Clinical Guidelines (2018), although an attempt to establish predictive and/or prognostic markers of clinical aggressiveness remains difficult. In this review, we focus on a group of pituitary tumours causing significant problems in clinical practice and requiring multidisciplinary input. We summarise updates in definitions of tumour invasiveness, aggressiveness and malignant transformation, as well as histological classification, and emphasise the new considerations regarding aggressive and malignant potential and its relationship to therapeutic strategies.

CLINICALLY SILENT ADRENOCORTICOTROPIC HORMONE-SECRETING CROOKE CELL ADENOMA PRESENTING AS UNILATERAL EAR PAIN

Objective

Crooke cell adenoma (CCA) is a rare tumor of the anterior pituitary. It is highly aggressive and carries significant risk of morbidity and mortality.

Methods

This report focuses on the presentation of this disease process and review diagnosis and treatment. The patient is a 64-year-old male with a history of resected pituitary adenoma of unknown pathology.

Results

The patient underwent serial magnetic resonance imaging surveillance for numerous years without recurrence of tumor, however eventually developed symptoms of worsening left ear pain over 3 weeks that rapidly evolved to include ptosis. Imaging revealed a new pituitary macroadenoma. Urgent surgical resection revealed histopathological diagnosis of CCA. Corticotroph adenomas represent a rare subset of pituitary tumors. Clinically silent pituitary tumors demonstrate relatively higher rates of cavernous sinus invasion (30% versus 18%) and progression or recurrence (34% versus 6%) when compared to nonfunctioning adenomas. In CCA, only 65% of patients have clinical features of Cushing disease at presentation. Twenty-four-hour urinary free cortisol is discussed in the literature as a potential tool, where a value 4 times the upper limit of normal was predictive of higher risk of having Crooke cell changes. With a recurrence rate of up to 60%, multimodal treatment (surgery and radiation) is preferred.

Conclusion

This case highlights early detection and treatment as keys to reducing the risk of morbidity and mortality from CCA. Currently, there are limited tools for identifying patients who are high risk for developing Crooke cell changes. Treatment modalities classically include surgery and radiotherapy. Adjuvant and novel chemotherapies are being explored.

Is it time to consider the expression of specific-pituitary hormone genes when typifying pituitary tumours?

The aim of the present study is to check whether we can replicate, in an independent series, previous results showing that the molecular study of pituitary-specific gene expression complements the inmunohistochemical identification of pituitary neuroendocrine tumours. We selected 112 patients (51 (46.4%) women; mean age 51.4±16 years; 102 macroadenomas (91.9%), 9 microadenomas (8.1%)) with complete clinical, radiological, immunohistochemical and molecular data from our data set of pituitary neuroendocrine tumours. Patients were different from those previously studied. We measured the expression of the pituitary-specific hormone genes and type 1 corticotrophin-releasing hormone and arginine vasopressin 1b receptors, by quantitative real-time polymerase chain reaction using TaqMan probes. Afterwards, we identified the different pituitary neuroendocrine tumour subtypes following the 2017 World Health Organization classification of pituitary tumours, calculating the concordance between their molecular and immuhistochemical identification. The concordance between molecular and immunohistochemical identification of functioning pituitary neuroendocrine tumours with the clinical diagnosis was globally similar to the previous series, where the SYBR Green technique was used instead of TaqMan probes. Our results also corroborated the poor correlation between molecular and immunohistochemical detection of the silent pituitary neuroendocrine tumour variants. This discrepancy was more remarkable in lactotroph, null-cell and plurihormonal pituitary neuroendocrine tumours. In conclusion, this study validates the results previously published by our group, highlighting a complementary role for the molecular study of the pituitary-specific hormone genes in the typification of pituitary neuroendocrine tumours subtypes.

The Epigenomic Landscape of Pituitary Adenomas Reveals Specific Alterations and Differentiates Among Acromegaly, Cushing's Disease and Endocrine-Inactive Subtypes

Purpose: Pituitary adenomas are one of the most common benign neoplasms of the central nervous system. Although emerging evidence suggests roles for both genetic and epigenetic factors in tumorigenesis, the degree to which these factors contribute to disease remains poorly understood.Experimental Design: A multiplatform analysis was performed to identify the genomic and epigenomic underpinnings of disease among the three major subtypes of surgically resected pituitary adenomas in 48 patients: growth hormone (GH)-secreting (n = 17), adrenocorticotropic hormone (ACTH)-secreting (n = 13, including 3 silent-ACTH adenomas), and endocrine-inactive (n = 18). Whole-exome sequencing was used to profile the somatic mutational landscape, whole-transcriptome sequencing was used to identify disease-specific patterns of gene expression, and array-based DNA methylation profiling was used to examine genome-wide patterns of DNA methylation.Results: Recurrent single-nucleotide and small indel somatic mutations were infrequent among the three adenoma subtypes. However, somatic copy-number alterations (SCNA) were identified in all three pituitary adenoma subtypes. Methylation analysis revealed adenoma subtype-specific DNA methylation profiles, with GH-secreting adenomas being dominated by hypomethylated sites. Likewise, gene-expression patterns revealed adenoma subtype-specific profiles. Integrating DNA methylation and gene-expression data revealed that hypomethylation of promoter regions are related with increased expression of GH1 and SSTR5 genes in GH-secreting adenomas and POMC gene in ACTH-secreting adenomas. Finally, multispectral IHC staining of immune-related proteins showed abundant expression of PD-L1 among all three adenoma subtypes.Conclusions: Taken together, these data stress the contribution of epigenomic alterations to disease-specific etiology among adenoma subtypes and highlight potential targets for future immunotherapy-based treatments. This article reveals novel insights into the epigenomics underlying pituitary adenomas and highlights how differences in epigenomic states are related to important transcriptome alterations that define adenoma subtypes. Clin Cancer Res; 24(17); 4126-36. ©2018 AACR.

Corticotrophic pituitary carcinoma with cervical metastases: case series and literature review

PURPOSE

Pituitary tumors are the second most common intracranial tumors, however, pituitary carcinoma is a rare clinical entity which represents only 0.1-0.2% of all pituitary tumors. Diagnosis of pituitary carcinoma requires the presence of metastasis. Early identification of pituitary carcinoma is difficult, and only recently have guidelines been published for the treatment of aggressive pituitary tumors. We present two cases from our institution, with a review of other cases available in literature in order to better characterize this rare disease.

METHODS

A retrospective review of two patients with pituitary carcinoma treated at a tertiary medical center was performed. The MEDLINE database was searched for all cases of pituitary carcinoma. Information for age at diagnosis, sex, pituitary tumor type, latency period from pituitary tumor to presentation of carcinoma, sites of metastasis, number of surgical therapies, radiation and chemotherapy, and survival after diagnosis were collected.

RESULTS

A total of 69 studies were available for review for a total of 72 unique cases. The average age at diagnosis was 46.3 years. The most common tumors were ACTH-secreting (34.7%), Prolactin-secreting (23.6%), and Null Cell (15.3%). The average latency period from pituitary tumor diagnosis to metastasis was 9 years. All patients underwent surgical therapy during their treatment, with an average of 2.76 procedures. The mortality rate was 54.8% with average time to death after diagnosis of approximately 10 months.

CONCLUSIONS

Pituitary carcinoma is a rare disease with high mortality rate and is a diagnostic and treatment challenge. Further study is required but is difficult due to its low incidence.

Clinical Parameters to Distinguish Silent Corticotroph Adenomas from Other Nonfunctioning Pituitary Adenomas

BACKGROUND

It is difficult to distinguish silent corticotroph adenomas (SCAs) from other nonfunctioning pituitary adenomas (NFPAs) preoperatively. This study aimed to determine the preoperative clinical parameters associated with SCAs.

METHODS

This was a retrospective single-center study of patients who underwent surgery for NFPAs during 2011-2016 in our tertiary hospital and who had preoperative combined pituitary function test (CPFT) and immunohistochemical staining results available. After we excluded patients with increased 24-hour urinary free cortisol to preclude overt Cushing's disease, 341 patients were finally enrolled. The medical records, including the CPFT and immunohistochemistry results, of the patients were reviewed.

RESULTS

The age and tumor size were similar between patients with SCAs and other NFPAs. The SCA group had a greater proportion of women (89.2% vs. 57.6%, P < 0.001), cavernous sinus invasion (35.1% vs. 20.7%, P = 0.047), and intratumoral hemorrhage on preoperative sella magnetic resonance imaging (32.4% vs. 9.2%, P < 0.001) compared with the NFPA group. In the preoperative CPFT, the cortisol response was not significantly different between groups. However, the peak adrenocorticotropic hormone (ACTH) (67.80 ± 49.83 vs. 85.67 ± 78.97 pg/mL, P = 0.061) tended to be lower, and the ΔACTH (53.71 ± 50.14 vs. 72.67 ± 75.82 pg/mL, P = 0.046) was significantly lower in SCAs. After we excluded patients with preoperative hypopituitarism caused by mass effects, the peak ACTH (69.39 ± 39.45 vs. 119.75 ± 89.84 pg/mL, P = 0.001) and ΔACTH (58.58 ± 36.51 vs. 107.66 ± 86.05 pg/mL, P = 0.001) were significantly lower in SCAs than in other NFPAs.

CONCLUSIONS

Female sex, cavernous sinus invasion, intratumoral hemorrhage on sella magnetic resonance imaging, and decreased ACTH response in the CPFT are independent indicators of SCAs.

Malignant transformation in non-functioning pituitary adenomas (pituitary carcinoma)

Non-functioning pituitary carcinomas (NFPC) are defined as tumours of adenophyseal origin with craniospinal or systemic dissemination, with the absence of a hormonal hypersecretion syndrome. These are a histologically heterogenous group of tumours, comprising gonadotroph, null cell, "silent" tumours of corticotroph, somatotroph or lactotroph cell lineages as well as plurihormonal Pit-1 tumours. NFPC are exceedingly rare, and hence few cases have been described. This review has identified 38 patients with NFPC reported in the literature. Recurrent invasive non-functioning pituitary adenomas (NFPA) were observed in a majority of patients. Various factors have been identified as markers of the potential for aggressive behaviour, including rapid tumour growth, growth after radiotherapy, gain or shift of hormone secretion and raised proliferative markers. Typically, there is a latency of several years from the original presentation with an NFPA to identification of metastases and only 5 cases reported with rapidly progressive malignant disease within 1 month of presentation. Therapeutic options include debulking surgery, radiation therapy and chemotherapy with temozolomide recommended as first line systemic treatment. Although long-term survivors are described, prognosis remains generally very poor (median survival 8 months). Improvements in molecular tumour profiling may assist in predicting tumour behaviour, guide therapeutic choices and identify novel therapies.

Histopathological classification of non-functioning pituitary neuroendocrine tumors

Non-functioning pituitary neuroendocrine tumors do not cause endocrine symptoms related to hypersecretion of adenohypophyseal hormones and are clinically characterized by symptoms due to growing sellar tumor mass. Histopathological classification of this tumor group has always been challenging due to their heterogeneity, limited knowledge on their biology, and diverse methodological problems. We have searched PubMed database for data related to the histopathological classification of non-functioning pituitary tumors and methods for its application. Principles of the classification and grading presented in the recently released 4th edition of the World Health Organization classification of endocrine tumors have been summarized. Based on the expression of anterior pituitary hormones and pituitary specific transcription factors, gonadotroph tumors dominate within the group of clinically non-functioning tumors, followed by corticotroph type; however, other less common types of the non-functioning tumors can be identified. Assessment of tumor cell proliferation is important to identify "high-risk adenomas." A few subtypes of non-functioning tumors belong to the category of potentially aggressive tumors, independent of the cell proliferation rate. Here, we present up to date criteria for the classification of clinically non-functioning pituitary tumors, offer a diagnostic approach for the routine clinical use, and emphasize a need for inclusion of prognostic and predictive markers in the classification.

Prognostic factors of regrowth in nonfunctioning pituitary tumors

Surgery is the treatment of choice for nonfunctioning pituitary tumors (NFPTs). Postoperative tumor regrowth during follow-up is present in about half of the patients with invasive NFPTs with residual tumor but occurs also in 15% of patient without residue. Therapeutic strategies should consider this risk of recurrence and the potential side effects associated with therapeutic options. Identification of prognostic markers is mandatory to help clinicians to predict the risk of recurrence and to choose the best strategy between conservative follow-up, second surgery, postoperative adjuvant radiation therapy, and medical treatment (dopamine agonists, somatostatin analogs). Recent advances in pathological classification may be the first step for identification of NFPTs with a high risk of recurrence.

Silent corticotroph adenomas

PURPOSE

Silent corticotroph adenomas (SCAs) present clinically as non-functioning adenomas (NFAs) but are immunopositive for adrenocorticotrophic hormone (ACTH) without biochemical and clinical manifestation of hypercortisolism. Pathologic examination of resected NFAs that demonstrate positive ACTH and/or TPIT expression confirms its corticotroph lineage. SCAs comprise up to 20% of NFAs and exhibit a higher rate of recurrence. Studies of molecular mechanisms have generated multiple hypotheses on SCA tumorigenesis, pathophysiology, and growth that as yet remain to be proven. An improved understanding of their pathologic and clinical characteristics is needed.

METHODS

A literature review was performed using PubMed to identify research reports and clinical case series on SCAs.

RESULTS

Up to date findings regarding epidemiology, mechanisms of pathogenesis, differentiation, progression, and growth, as well as clinical presentation, postoperative course, and treatment options for patients with SCAs are presented. Pooled results demonstrate that 25-40% of cases show cavernous sinus invasion, preoperative hypopituitarism, new-onset hypopituitarism, and recurrence.

CONCLUSION

This article reviews the incidence, molecular pathology, and clinical behavior of these unique non-functioning pituitary corticotroph adenomas, and highlights the need for rigorous monitoring for recurrences and hypopituitarism in patients with SCAs.

Predictors of silent corticotroph adenoma recurrence; a large retrospective single center study and systematic literature review

PURPOSE

Silent corticotroph adenomas (SCAs) are clinically silent and non-secreting, but exhibit positive adrenocorticotropic hormone (ACTH) immunostaining. We characterized a single center cohort of SCA patients, compared the SCAs to silent gonadotroph adenomas (SGAs), identified predictors of recurrence, and reviewed and compared the cohort to previously published SCAs cases.

METHODS

Retrospective review of SCA and SGA surgically resected patients over 10 years and 6 years, respectively. Definitions; SCA-no clinical or biochemical evidence of Cushing's syndrome and ACTH positive immunostaining, and SGA-steroidogenic factor (SF-1) positive immunostaining. A systematic literature search was undertaken using Pubmed and Scopus.

RESULTS

Review revealed 814 pituitary surgeries, 39 (4.8%) were SCAs. Mean follow-up was 6.4 years (range 0.5-23.8 years). Pre-operative magnetic resonance imaging demonstrated sphenoid and/or cavernous sinus invasion in 44%, 33% were > 50% cystic, and 28% had high ACTH levels pre-operatively. Compared to SGAs (n = 70), SCAs were of similar size and invasiveness (2.5 vs. 2.9 cm, p = 0.2; 44 vs. 41%, p = 0.8, respectively), but recurrence rate was higher (36 vs. 10%, p = 0.001) and more patients received radiation therapy (18 vs. 3%, p = 0.006). Less cystic tumors (0 vs. 50%, p < 0.001) and higher pre-operative ACTH levels (54 vs. 28 pg/ml, p = 0.04) were predictors of recurrence for SCAs.

CONCLUSION

This review is unique; a strict definition of SCA was used, and single center SCAs were compared with SGAs and with SCAs literature reviewed cases. We show that SCAs are aggressive and identify predictors of recurrence. Accurate initial diagnosis, close imaging and biochemical follow up are warranted.

European Society of Endocrinology Clinical Practice Guidelines for the management of aggressive pituitary tumours and carcinomas

BACKGROUND

Pituitary tumours are common and easily treated by surgery or medical treatment in most cases. However, a small subset of pituitary tumours does not respond to standard medical treatment and presents with multiple local recurrences (aggressive pituitary tumours) and in rare occasion with metastases (pituitary carcinoma). The present European Society of Endocrinology (ESE) guideline aims to provide clinical guidance on diagnosis, treatment and follow-up in aggressive pituitary tumours and carcinomas.

METHODS

We decided upfront, while acknowledging that literature on aggressive pituitary tumours and carcinomas is scarce, to systematically review the literature according to the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. The review focused primarily on first- and second-line treatment in aggressive pituitary tumours and carcinomas. We included 14 single-arm cohort studies (total number of patients = 116) most on temozolomide treatment (n = 11 studies, total number of patients = 106). A positive treatment effect was seen in 47% (95% CI: 36-58%) of temozolomide treated. Data from the recently performed ESE survey on aggressive pituitary tumours and carcinomas (165 patients) were also used as backbone for the guideline. SELECTED RECOMMENDATION: (i) Patients with aggressive pituitary tumours should be managed by a multidisciplinary expert team. (ii) Histopathological analyses including pituitary hormones and proliferative markers are needed for correct tumour classification. (iii) Temozolomide monotherapy is the first-line chemotherapy for aggressive pituitary tumours and pituitary carcinomas after failure of standard therapies; treatment evaluation after 3 cycles allows identification of responder and non-responder patients. (iv) In patients responding to first-line temozolomide, we suggest continuing treatment for at least 6 months in total. Furthermore, the guideline offers recommendations for patients who recurred after temozolomide treatment, for those who did not respond to temozolomide and for patients with systemic metastasis.

Clinical profile of silent growth hormone pituitary adenomas; higher recurrence rate compared to silent gonadotroph pituitary tumors, a large single center experience

PURPOSE

Study and comparison of characteristics of silent growth hormone adenomas (SGHA), silent corticotroph adenomas (SCA), and silent gonadotroph adenomas (SGA) in a single institution cohort of surgically treated pituitary adenomas.

METHODS

Retrospective analysis of SGHA surgically resected over 10 years: SGHA was defined as no clinical or biochemical evidence of acromegaly and positive GH immunostaining.

RESULTS

Of 814 pituitary surgeries; 2.1% (n = 17) were SGHA, 4.5% (n = 37) SCA, and 18.9% (n = 70/371; 2011-2016) SGA. Mean age at SGHA diagnosis was 43 years, with a large female predominance (82%). Mean tumor size and cavernous/sphenoid sinus invasiveness for SGHA, SCA, and SGA were 1.5 ± 1.0 cm and 25%, 2.5 ± 1.2 cm and 43%, 2.9 ± 2.0 cm and 41%, respectively (tumor size p = 0.009, SGHA vs. SGA, and invasion p; not-significant). During mean follow-up of 3.9 years, two patients (11%) developed elevated insulin-like growth factor-1 and five patients (29%) required a second surgery for tumor recurrence. Rate of surgical reintervention was similar to SCA (31%), but higher than SGA (10%) (p = 0.035, SGHA vs. SGA), and 18% underwent radiation therapy, similar to SCA (19%, p; not-significant) but higher than SGA (2.9%, p = 0.018).

CONCLUSION

This is the largest single center study characterizing SGHA behavior with SGA and SCA control groups in a cohort of surgically resected pituitary adenomas. SGHA present mostly in young females, and should be closely followed due to their higher likelihood of recurrence and potential of progression to clinical acromegaly. We propose that a complete hormonal staining panel be routinely performed for all pituitary adenomas.

The 2017 World Health Organization classification of tumors of the pituitary gland: a summary

The 4th edition of the World Health Organization (WHO) classification of endocrine tumors has been recently released. In this new edition, major changes are recommended in several areas of the classification of tumors of the anterior pituitary gland (adenophypophysis). The scope of the present manuscript is to summarize these recommended changes, emphasizing a few significant topics. These changes include the following: (1) a novel approach for classifying pituitary neuroendocrine tumors according to pituitary adenohypophyseal cell lineages; (2) changes to the histological grading of pituitary neuroendocrine tumors with the elimination of the term "atypical adenoma;" and (3) introduction of new entities like the pituitary blastoma and re-definition of old entities like the null-cell adenoma. This new classification is very practical and mostly based on immunohistochemistry for pituitary hormones, pituitary-specific transcription factors, and other immunohistochemical markers commonly used in pathology practice, not requiring routine ultrastructural analysis of the tumors. Evaluation of tumor proliferation potential, by mitotic count and Ki-67 labeling index, and tumor invasion is strongly recommended on individual case basis to identify clinically aggressive adenomas. In addition, the classification offers the treating clinical team information on tumor prognosis by identifying specific variants of adenomas associated with an elevated risk for recurrence. Changes in the classification of non-neuroendocrine tumors are also proposed, in particular those tumors arising in the posterior pituitary including pituicytoma, granular cell tumor of the posterior pituitary, and spindle cell oncocytoma. These changes endorse those previously published in the 2016 WHO classification of CNS tumors. Other tumors arising in the sellar region are also reviewed in detail including craniopharyngiomas, mesenchymal and stromal tumors, germ cell tumors, and hematopoietic tumors. It is hoped that the 2017 WHO classification of pituitary tumors will establish more biologically and clinically uniform groups of tumors, make it possible for practicing pathologists to better diagnose these tumors, and contribute to our understanding of clinical outcomes for patients harboring pituitary tumors.

Overview of the 2017 WHO Classification of Pituitary Tumors

This review focuses on discussing the main changes on the upcoming fourth edition of the WHO Classification of Tumors of the Pituitary Gland emphasizing histopathological and molecular genetics aspects of pituitary neuroendocrine (i.e., pituitary adenomas) and some of the non-neuroendocrine tumors involving the pituitary gland. Instead of a formal review, we introduced the highlights of the new WHO classification by answering select questions relevant to practising pathologists. The revised classification of pituitary adenomas, in addition to hormone immunohistochemistry, recognizes the role of other immunohistochemical markers including but not limited to pituitary transcription factors. Recognizing this novel approach, the fourth edition of the WHO classification has abandoned the concept of "a hormone-producing pituitary adenoma" and adopted a pituitary adenohypophyseal cell lineage designation of the adenomas with subsequent categorization of histological variants according to hormone content and specific histological and immunohistochemical features. This new classification does not require a routine ultrastructural examination of these tumors. The new definition of the Null cell adenoma requires the demonstration of immunonegativity for pituitary transcription factors and adenohypophyseal hormones Moreover, the term of atypical pituitary adenoma is no longer recommended. In addition to the accurate tumor subtyping, assessment of the tumor proliferative potential by mitotic count and Ki-67 index, and other clinical parameters such as tumor invasion, is strongly recommended in individual cases for consideration of clinically aggressive adenomas. This classification also recognizes some subtypes of pituitary neuroendocrine tumors as "high-risk pituitary adenomas" due to the clinical aggressive behavior; these include the sparsely granulated somatotroph adenoma, the lactotroph adenoma in men, the Crooke's cell adenoma, the silent corticotroph adenoma, and the newly introduced plurihormonal Pit-1-positive adenoma (previously known as silent subtype III pituitary adenoma). An additional novel aspect of the new WHO classification was also the definition of the spectrum of thyroid transcription factor-1 expressing pituitary tumors of the posterior lobe as representing a morphological spectrum of a single nosological entity. These tumors include the pituicytoma, the spindle cell oncocytoma, the granular cell tumor of the neurohypophysis, and the sellar ependymoma.

Outcome of Nonfunctioning Pituitary Adenomas That Regrow After Primary Treatment: A Study From Two Large UK Centers

CONTEXT

Despite the major risk of regrowth of clinically nonfunctioning pituitary adenomas (CNFAs) after primary treatment, systematic data on the probability of further tumor progression and the effectiveness of management approaches are lacking.

OBJECTIVE

To assess the probability of further regrowth(s), predictive factors, and outcomes of management approaches in patients with CNFA diagnosed with adenoma regrowth after primary treatment.

PATIENTS, DESIGN, AND SETTING

Retrospective cohort study of 237 patients with regrown CNFA managed in two UK centers.

RESULTS

Median follow-up was 5.9 years (range, 0.4 to 37.7 years). The 5-year second regrowth rate was 35.3% (36.2% after surgery; 12.5% after radiotherapy; 12.7% after surgery combined with radiotherapy; 63.4% with monitoring). Of those managed with monitoring, 34.8% eventually were offered intervention. Type of management and sex were risk factors for second regrowth. Among those with second adenoma regrowth, the 5-year third regrowth rate was 26.4% (24.4% after surgery; 0% after radiotherapy; 0% after surgery combined with radiotherapy; 48.3% with monitoring). Overall, patients with a CNFA regrowth had a 4.4% probability of a third regrowth at 5 years and a 10.0% probability at 10 years; type of management of the first regrowth was the only risk factor. Malignant transformation was diagnosed in two patients.

CONCLUSIONS

Patients with regrown CNFA after primary treatment continue to carry considerable risk of tumor progression, necessitating long-term follow-up. Management approach to the regrowth was the major factor determining this risk; monitoring had >60% risk of progression at 5 years, and a substantial number of patients ultimately required intervention.

Silent Crooke's cell corticotroph adenoma of the pituitary gland presenting as delayed puberty

Summary

Corticotroph adenomas are extremely rare in children and adolescents. We present a 15-year-old boy who was investigated for delayed puberty (A1P2G1, bilateral testicular volumes of 3 mL each). There was no clinical or laboratory evidence suggestive of chronic illness, and the initial clinical impression was constitutional delay in puberty. Subsequently, MRI scan of the brain revealed the presence of a mixed cystic and solid pituitary lesion slightly displacing the optic chiasma. The lesion was removed by transphenoidal surgery and the biopsy confirmed the lesion to be pituitary adenoma. Furthermore, the adenoma cells also had Crooke’s hyaline changes and were intensely positive for ACTH. However there was no clinical/biochemical evidence of ACTH excess. There was a spontaneous pubertal progression twelve months after the surgery (A2P4G4, with bilateral testicular volume of 8 mL). Crooke’s cell adenoma is an extremely rare and aggressive variant of corticotroph adenoma that can uncommonly present as a silent corticotroph adenoma in adults. We report for the first time Crooke’s cell adenoma in an adolescent boy presenting with delayed puberty.

Learning points:

Long-term results of hypofractionated stereotactic radiotherapy with CyberKnife for growth hormone-secreting pituitary adenoma: evaluation by the Cortina consensus

The aim of the present study was to evaluate the safety and feasibility of hypofractionated stereotactic radiotherapy (SRT) with CyberKnife for growth hormone-secreting pituitary adenoma (GH-PA). Fifty-two patients with GH-PA were treated with hypofractionated SRT between September 2001 and October 2012. Eight patients had clinically silent GH-PA and 44 were symptomatic. Only 1 patient was inoperable. The other patients had recurrent or postoperative residual tumors on MRI. All patients had received pharmacotherapy prior to SRT with a somatostatin analog, dopamine agonist, and/or GH receptor antagonist. The marginal doses were 17.4-26.8 Gy for the 3-fraction schedule and 20.0-32.0 Gy for the 5-fraction schedule. Endocrinological remission was assessed by the Cortina consensus criteria 2010 (random GH <1 ng/ml or nadir GH after an oral glucose tolerance test <0.4 ng/ml and normalization of age- and sex-adjusted insulin-like growth factor-1). The median follow-up period was 60 months (range 27-137). The 5-year overall survival, local control, and disease-free survival rates were 100, 100, and 96 %, respectively. Nine patients (5 clinically silent and 4 symptomatic patients) satisfied the Cortina criteria without receiving further pharmacotherapy, whereas the remaining 43 patients did not. No post-SRT grade 2 or higher visual disorder occurred. Symptomatic post-SRT hypopituitarism was observed in 1 patient. CyberKnife hypofractionated SRT is safe and effective when judged by imaging findings for GH-PA. However, it may be difficult to satisfy the Cortina consensus criteria in most symptomatic patients with SRT alone. Further investigations of optimal treatments are warranted.

Oncogene-Induced Senescence in Pituitary Adenomas--an Immunohistochemical Study

Oncogene-induced senescence (OIS) serves as an initial barrier to cancer development, being proposed as a possible explanation for the usually benign behavior of the pituitary adenomas. We aimed to explore the immunohistochemical expression of the OIS markers, senescence-associated lysosomal β-galactosidase (SA-β-GAL), p16, and p21 in different types of 345 pituitary adenomas and compared it with the expression in the normal pituitary and in the specimens from the repeated surgeries. SA-β-GAL was overexpressed in the pituitary adenomas, compared to the normal pituitaries. Growth hormone (GH) producing adenomas showed the strongest SA-β-GAL, with densely granulated (DG)-GH adenomas more reactive than the sparsely granulated (SG). Nuclear p21 was decreased in the adenomas, except for the SG-GH adenomas that had higher p21 than the normal pituitaries and the other adenomas. p16 was significantly lower in the adenomas, without type-related differences. SA-β-GAL was slightly lower and p16 slightly higher in the recurrences. Our findings indicate alterations of the senescence program in the different types of pituitary adenomas. Activation of senescence in the pituitary adenomas presents one possible explanation for their usually benign behavior, at least in the GH adenomas that show a synchronous increase of two OIS markers. However, subdivision into GH adenoma subtypes reveals differences that reflect complex regulatory mechanisms influenced by the interplay between the granularity pattern and the hormonal factors, with possible impact on the different clinical behavior of the SG- and DG-GH adenoma subtypes. p16 seems to have a more prominent role in the pituitary tumorigenesis than in the senescence. Recurrent growth in a subset of the pituitary adenomas is not associated with consistent changes in the senescence pattern.