Atypical pituitary adenomas: clinical characteristics and role of ki-67 and p53 in prognostic and therapeutic evaluation. A series of 50 patients

Identifying prognostic predictors for postoperative pituitary neuroendocrine tumour recurrence: an integrated clinical, radiological, and immunohistochemistry assessment

OBJECTIVE

Pituitary neuroendocrine tumours (PitNETs) are the second most common type of intracranial tumour. Several studies have explored the prognostic factors for PitNETs. However, prognostic factors for postoperative PitNET recurrence remain not fully understood. This study aimed to explore potential prognostic factors for PitNET recurrence, such as surrounding tissue invasion and the extent of surgical resection in patients with postoperative PitNETs.

METHODS

We included 106 patients who underwent PitNET surgery between 2013 and 2018, dividing them into two groups: those with recurrence and those without recurrence. Tumours were classified based on demographics, neuroradiological, and immunohistological characteristics. Univariate and multivariate analyses were used to determine factors predicting recurrence. Kaplan-Meier plots and log-rank tests were used to analyse each independent factor based on the cumulative 5-year recurrence rate.

RESULTS

During the 5-year follow-up period, 29.2% of the patients (n = 31) had disease recurrence. Univariate analysis showed that predictors of recurrence included cavernous and sphenoid sinus invasions, optic chiasm compression, larger tumour volume, giant adenoma >4 cm, and gross total resection (GTR). Multivariate analysis showed that lactotroph tumour type, sphenoid sinus invasion, and GTR were independent predictors. Kaplan-Meier analysis revealed significant differences in the 5-year recurrence rate among the three independent predictors, with significantly lower recurrence rate in patients with lactotroph tumours and GTR, and a significantly higher recurrence risk in patients with sphenoid sinus invasion.

CONCLUSIONS

Lactotroph tumour type, sphenoid sinus invasion, and GTR are independent predictors of postoperative PitNET recurrence. This study provides insights into the factors affecting postoperative PitNET recurrence.

PD-L1 Expression in Pituitary Neuroendocrine Tumors/Pituitary Adenomas

BACKGROUND AND AIM

About a third of Pituitary Neuroendocrine Tumors (PitNETs) may show aggressive behavior. Many efforts have been performed for identifying possible predictive factors to early determine the future behavior of PitNETs. Programmed cell death ligand 1 (PD-L1) expression was associated with a more aggressive biology in different solid tumors, but its role in PitNET is not well-established yet. Our study aims to analyze PD-L1 expression in a surgical cohort of PitNETs to determine its association with radiological invasion and pathology findings, as well as with long-term recurrence rates.

METHODS

We performed a retrospective analysis in a series of 86 PitNETs. Clinical presentation and radiological features of the preoperative period were collected, as well as pathological data and follow-up data. The rate of PD-L1 expression was immunohistochemically evaluated and expressed as a tumor proportion score (TPS). We assessed its relationship with cavernous sinus invasion and Trouillas' classification as primary outcomes. Secondary outcomes included the TPS' relationship with histopathological markers of proliferation, hormonal expression, tumor size and long-term recurrence rates. We calculated the optimal cut-point for the primary outcomes while maximizing the product of the sensitivity and specificity and then we evaluated the significance of secondary outcomes with logistic regression analysis.

RESULTS

Eighty-six patients were included in the analysis; 50 cases were non-functional PitNETs. The TPS for PD-L1 showed a highly right-skewed distribution in our sample, as 30.2% of patients scored 0. Using Trouillas' classification, we found that "proliferative" cases have a significantly higher probability to express PD-L1 in more than 30% of tumor cells (OR: 5.78; CI 95%: 1.80-18.4). This same cut-point was also associated with p53 expression. A positive association was found between PD-L1 expression and GH expression (p = 0.001; OR: 5.44; CI 95%: 1.98-14.98), while an inverse relationship was found with FSH/LH expression (p = 0.014; OR = 0.27, CI 95%: 0.10-0.76). No association was found with CS invasion, tumor size, bone erosion or dura invasion. We could not find any association between PD-L1 expression and recurrence.

CONCLUSIONS

PD-L1 expression was associated with proliferative grades of Trouillas' classification and p53 expression. We also confirmed a higher expression of PD-L1 in somatotroph tumors. Larger studies are necessary to investigate the relationship between PD-L1 expression and aggressive behaviors.

Molecular targets in acromegaly

Molecular therapeutic targets in growth hormone (GH)-secreting adenomas range from well-characterized surface receptors that recognize approved drugs, to surface and intracellular markers that are potential candidates for new drug development. Currently available medical therapies for patients with acromegaly bind to somatostatin receptors, GH receptor, or dopamine receptors, and lead to attainment of disease control in most patients. The degree of control is variable: however, correlates with both disease aggressiveness and tumor factors that predict treatment response including somatostatin receptor subtype expression, granulation pattern, kinases and their receptors, and other markers of proliferation. A better understanding of the mechanisms underlying these molecular markers and their relationship to outcomes holds promise for expanding treatment options as well as a more personalized approach to treating patients with acromegaly.

A case of aggressive pituitary neuroendocrine tumour with extremely rapid progression: possible diagnostic value of TERT promoter methylation

Most pituitary adenoma/neuroendocrine tumours (PitNET) are histologically benign and grow slowly; however, a subset of these tumours exhibit a more aggressive clinical course characterized by local invasiveness and early recurrence. These high-risk PitNETs often require multiple surgeries and radiation over several years and may eventually acquire carcinomatous characteristics, such as metastasis in some cases. Herein, we report a rare case of PitNET causing oculomotor paresis with extremely rapid recurrence only 3 months after initial surgery, followed by lethal liver metastasis. Preoperative magnetic resonance imaging and intraoperative findings were consistent with typical PitNETs, other than moderate invasion of the cavernous sinus. Pathological examination of the specimen obtained from the initial transsphenoidal surgery revealed increased mitosis and elevated rates of cells positive for Ki-67 and p53. Based on the immunohistochemical assessment for transcription factors and pituitary hormones, the diagnosis was determined to be a silent sparsely granulated corticotroph PitNET with focal malignant transformation. Aggressive features represented by Ki-67 and p53 positivity were more robust in recurrent and metastatic specimens, but hormone immunostaining was decreased. Epigenetic analysis revealed methylation of the telomerase reverse transcriptase (TERT) promoter in the tumour, resulting in TERT upregulation. Despite extensive research, markers for distinguishing extremely aggressive PitNETs have not been determined. Although further analysis is needed, our case demonstrates the possible usefulness of assessing TERT promoter methylation status in the stratification of recurrence risk in extremely high-risk variants of PitNET.

Machine Learning in Pituitary Surgery

Machine learning applications in neurosurgery are increasingly reported for diverse tasks such as faster and more accurate preoperative diagnosis, enhanced lesion characterization, as well as surgical outcome, complications and healthcare cost prediction. Even though the pertinent literature in pituitary surgery is less extensive with respect to other neurosurgical diseases, past research attempted to answer clinically relevant questions to better assist surgeons and clinicians. In the present chapter we review reported ML applications in pituitary surgery including differential diagnosis, preoperative lesion characterization (immunohistochemistry, cavernous sinus invasion, tumor consistency), surgical outcome and complication predictions (gross total resection, tumor recurrence, and endocrinological remission, cerebrospinal fluid leak, postoperative hyponatremia). Moreover, we briefly discuss from a practical standpoint the current barriers to clinical translation of machine learning research. On the topic of pituitary surgery, published reports can be considered mostly preliminary, requiring larger training populations and strong external validation. Thoughtful selection of clinically relevant outcomes of interest and transversal application of model development pipeline-together with accurate methodological planning and multicenter collaborations-have the potential to overcome current limitations and ultimately provide additional tools for more informed patient management.

Outcomes of transsphenoidal surgery in dopamine agonist-resistant prolactinomas: a retrospective study

PURPOSE

Dopamine agonists (DA) comprise first-line treatment for prolactinomas. However, some patients show no response to DA and are considered resistant. In this study, we retrospectively analyzed the outcomes of DA-resistant prolactinoma patients after transsphenoidal surgery (TSS).

METHODS

A total of 94 consecutive patients with DA-resistant prolactinomas who underwent TSS were retrospectively enrolled in the present study. Early postoperative remission rate, prolactin (PRL) levels, and recurrence rate were analyzed.

RESULTS

Of 94 DA-resistant patients, 47 (50%) achieved early remission 1 week post-surgery, including 41.18% of macroprolactinoma patients and 73.08% of microprolactinoma patients. PRL levels on the first postoperative day were significantly lower than preoperative PRL levels (p < 0.001). Total resection rate in macro- and microprolactinomas were, respectively, 75 and 96.15%. A recurrence of hyperprolactinemia and tumor was, respectively, found in 31.91 and 19.15% of patients with a follow-up of 39.53 ± 2.172 months (range 3-86). A higher hyperprolactinemia recurrence was observed in patients with invasive prolactinomas (p = 0.021) or preoperative PRL levels ≥ 200 ng/ml (p = 0.029). Univariate logistic regression indicated that larger maximum tumor diameter (p = 0.045), invasive prolactinomas (p = 0.002), and absence of early postoperative remission (p = 0.004) were significant predictors of tumor recurrence. However, using multivariate stepwise logistic regression, only invasiveness and early postoperative remission remained significant.

CONCLUSION

Tumor invasiveness and preoperative PRL levels were significant predictors of hyperprolactinemia recurrence after TSS. For tumor recurrence, invasiveness and early postoperative remission were independent predictors.

Aggressive pituitary neuroendocrine tumors: current practices, controversies, and perspectives, on behalf of the EANS skull base section

Aggressive pituitary neuroendocrine tumors (APT) account for 10% of pituitary tumors. Their management is a rapidly evolving field of clinical research and has led pituitary teams to shift toward a neuro-oncological-like approach. The new terminology "Pituitary neuroendocrine tumors" (PitNet) that was recently proposed to replace "pituitary adenomas" reflects this change of paradigm. In this narrative review, we aim to provide a state of the art of actual knowledge, controversies, and recommendations in the management of APT. We propose an overview of current prognostic markers, including the recent five-tiered clinicopathological classification. We further establish and discuss the following recommendations from a neurosurgical perspective: (i) surgery and multi-staged surgeries (without or with parasellar resection in symptomatic patients) should be discussed at each stage of the disease, because it may potentialize adjuvant medical therapies; (ii) temozolomide is effective in most patients, although 30% of patients are non-responders and the optimal timeline to initiate and interrupt this treatment remains questionable; (iii) some patients with selected clinicopathological profiles may benefit from an earlier local radiotherapy and/or chemotherapy; (iv) novel therapies such as VEGF-targeted therapies and anti-CTLA-4/anti-PD1 immunotherapies are promising and should be discussed as 2nd or 3rd line of treatment. Finally, whether neurosurgeons have to operate on "pituitary adenomas" or "PitNets," their role and expertise remain crucial at each stage of the disease, prompting our community to deal with evolving concepts and therapeutic resources.

Aggressive Pituitary Adenoma Not Fulfilling the New High-Risk Criteria with Progression after 18-Year Stable Clinical Course: Case Report

BACKGROUND

 The World Health Organization (WHO) classification of tumors of the endocrine organs was revised in 2017. The term atypical adenoma is no longer recommended, and tumors with rapid growth, radiologic invasion, and high K_i-67 labeling index are defined as high-risk adenomas. In this article, we present the case of an aggressive pituitary adenoma not fulfilling the new high-risk criteria with extraordinary rapid progression after very long stable disease, and discuss the remaining problem of the new criteria in terms of a complicated balance between pathologic findings and clinical features.

CASE DESCRIPTION

 A 67-year-old man was admitted with sellar tumor. Serum prolactin concentration was high at 4,552.2 ng/mL. Transsphenoidal surgery achieved subtotal removal. Histologic diagnosis was lactotroph cell adenoma, and K_i-67 labeling index was 2.6%. Postoperatively, magnetic resonance imaging revealed no evidence of tumor regrowth, but terguride or cabergoline administration was continued for slight hyperprolactinemia. Second surgery was performed 18 years after initial surgery because the tumor showed extraordinary rapid regrowth and hyperprolactinemia of 969 ng/mL. Histologic diagnosis was lactotroph cell adenoma with K_i-67 labeling index of 28.9% and positive immunoreactivity for p53. This case could be diagnosed as a high-risk adenoma from the beginning of treatment based on the WHO 2017 criteria, but the clinical course was unusually long and the indication of aggressive adjuvant therapy after initial surgery remained unsolved.

CONCLUSION

 Pathologic confirmation for the present definition would be expected to assess the cutoff between typical adenomas and aggressive tumors.

Bevacizumab in Aggressive Pituitary Adenomas - Experience with 3 Patients

OBJECTIVE

To investigate bevacizumab as alternative treatment of aggressive pituitary adenomas after exhaustion of standard therapies.

DESIGN AND METHODS

Retrospectively, 3 patients undergoing microscopic transsphenoidal surgery of aggressive pituitary adenomas from 2008 till 2018 that were treated with bevacizumab were identified. Development of disease and treatment were evaluated.

RESULTS

Two patients suffered from ACTH-secreting adenomas, one from a non-functioning adenoma. All patients underwent multiple surgical, chemo- and radiotherapeutical approaches including temozolomide, showing favorable results in one patient. Deterioration of clinical condition in all patients led to an individual, palliative attempt of bevacizumab. Patients 1 and 2 showed a decrease of ACTH after first administrations, but therapy had to be ended shortly after due to a further deterioration of their condition. Patient 3 showed a stabilization of the disease for 18 months. Patients died 8, 15 and 7 years after initial diagnosis, respectively, and 2, 4, and 24 months after initiation of bevacizumab therapy, respectively.

CONCLUSION

The demonstrated results suggest a considerable effect of bevacizumab in aggressive pituitary adenomas. The advanced stage of disease in all three patients, the overall short period of administration and just one patient showing a clinical benefit do not allow a general statement on the effectiveness. At the current stage of clinical experience, an approach with bevacizumab can be considered as an individual palliative attempt of treatment, when standard treatments are exhausted. Our results underline the need for further studies to evaluate this drug as potential player in therapy resistant aggressive pituitary tumors.

Ki67 in endocrine neoplasms: to count or not to count, this is the question! A systematic review from the English language literature

BACKGROUND

Endocrine neoplasms are generally slow-growing tumors that can show hormonal activity and give metastases. In most cases they are benign and clearly malignant forms are easy to diagnose. However, borderline forms may occur and be, for the pathologists, very difficult to classify. In these cases, there is a strong need to identify factors that may aid. Official classification systems for endocrine neoplasms are based on the evaluation of proliferation and, in most cases, they rely on mitotic count. In support, the study of Ki67 is carried out which, however, has not yet been included in any official classification system, except for neuroendocrine neoplasms of the gastro-entero-pancreatic tract.

PURPOSE

The aim of the present study was to investigate the proven or unproven role of Ki67 in endocrine neoplasms, in different districts, in order to bring to light the substantial differences, in terms of proliferation, existing between neoplasms so similar, but at the same time, so different.

METHODS

A thorough search of English language literature was performed, looking for articles concerning Ki67 in five endocrine neoplasms (pituitary adenomas, thyroid neoplasms, adrenocortical neoplasms, pheochromocytomas and paragangliomas).

RESULTS

From 2170, 236 articles were selected and it was seen that the endocrine neoplasm in which Ki67 was most studied was the pituitary, where it still shows a controversial role. In other neoplasms different roles were identified.

CONCLUSION

The pathologist should be aware of the contribution that this proliferative marker can give to the diagnosis and, sometimes, to the therapy selection, for the clinician.

World Health Ozganization 2017 Classification of Pituitary Tumors

The 2017 (fourth edition) World Health Organization Classification of Endocrine Tumors has recommended major changes in classification of tumors of the pituitary gland and region. In addition to the accurate tumor subtyping, assessment of the tumor proliferative potential (mitotic and/or Ki-67 index) and other clinical parameters such as tumor invasion is strongly recommended in individual cases for consideration of clinically aggressive adenomas. It is expected that this new WHO classification will establish more uniform biologically and clinically groups of pituitary tumors and contribute to understanding of clinical outcomes for patients harboring pituitary tumors.

MicroRNAs expression in pituitary tumors: differences related to functional status, pathological features, and clinical behavior

BACKGROUND

MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression at post-transcriptional level, having a role in many biological processes, such as control of cell proliferation, cell cycle, and cell death. Altered miRNA expression has been reported in many neoplasms, including pituitary adenomas (PAs).

PURPOSE

In this study, we aimed to evaluate the expression of 20 miRNAs involved in pathways relevant to pituitary pathophysiology, in PAs and normal pituitary tissue and to correlate their expression profile with clinical and pathological features.

METHODS

Pituitary tumor samples were obtained during transphenoidal surgery from patients with non-functioning (NFPA, n = 12) and functioning (n = 11, 5 GH-, 3 ACTH-, 3 PRL-omas) PAs. The expression of selected miRNAs in PAs and in normal pituitary was analyzed by RT-qPCR. miRNAs expression was correlated with demographic, clinical, and neuroradiological data and with histopathological features including pituitary hormones immunostaining, Ki-67 proliferation index, and p53 immunohistochemistry evaluation.

RESULTS

All evaluated miRNAs except miR-711 were expressed in both normal and tumor pituitary tissue. Seventeen miRNAs were significantly down-regulated in pituitary tumors compared to normal pituitary. miRNAs were differentially expressed in functioning PAs or in NFPAs, as in the latter group miR-149-3p (p = 0.036), miR-130a-3p (p = 0.014), and miR-370-3p (p = 0.026) were significantly under expressed as compared to functioning tumors. Point-biserial correlation analysis demonstrated a negative correlation between miR-26b-5p and Ki-67 (p = 0.031) and between miR-30a-5p and 'atypical' morphological features (p = 0.038) or cavernous sinus invasion (p = 0.049), while 508-5p was inversely correlated with clinical aggressiveness (p = 0.043).

CONCLUSIONS

In this study, we found a significant down-regulation of 17 miRNAs in PAs vs normal pituitary, with differential expression profile related to functional status and tumor aggressiveness.

Are aggressive pituitary tumors and carcinomas two sides of the same coin? Pathologists reply to clinician's questions

Pituitary adenohypophyseal tumors are considered as benign and termed "adenomas". However, many tumors are invasive and a proportion of these exhibit an "aggressive behavior" with premature death due to progressive growth. Only very rare (0.2%) tumors with metastases are considered malignant and termed "carcinomas". Taking into account this variability in behavior and the oncological definition, pathologists have proposed changing the term adenoma to tumor. Here we explain why use the term tumor instead of adenoma and identify tumor characteristics, associated with a high risk for poor prognosis. In a cohort of 125 tumors with aggressive behavior (APT) and 40 carcinomas with metastases (PC), clinical and pathological features were very similar. The comparison of this cohort (APT+PC) with a reference surgical cohort of 374 unselected patients clearly shows that the two cohorts differ greatly, especially the percentage of tumors with Ki67 ≥ 10% (35%vs3%; p < 0.001). A five-tiered prognostic classification, associating invasion and proliferation, identified grade 2b tumors (invasive and proliferative), with a high risk of recurrence/progression. Because half of the APT+ PC tumors have a Ki67 index ≥10%, and 80% of them show 2 or 3 positive markers of proliferation, we suggest that tumors that are clinically aggressive, invasive and highly proliferative with a Ki67 ≥ 10%, represent tumors with malignant potential. The percentage of grade 2b tumors, suspected of malignancy, which will become aggressive tumors or carcinomas is unknown. It is probably very low, but higher than 0.2% in surgical series. Early identification and active treatment of these aggressive tumors is needed to decrease morbidity and prolong survival.

RASSF10 regulates bone invasion of growth hormone-secreting adenomas via exosomes

BACKGROUND

Invasion of pituitary growth hormone-secreting adenoma into surrounding tissues poses a challenge for complete resection in surgery, which is the main reason for recurrence of this type of cancer. Studies have shown that abnormal methylation of RASSF10 can promote the expression of MDM2 and regulate the tumor microenvironment by affecting the secretion of exosomes. In the present study, we aim to uncover the specific underlying mechanism of this effect.

METHOD

Transwell co-culture assays was performed using GT1.1 cells or exosomes and RAW264.7 cells. RAW264.7 cells were collected for invasion, proliferation and apoptosis assays, RT-qPCR and western blotting. RNA-seq was performed and used to assess the potential molecular pathways of the effect of GT1.1 cell-exosomes on RAW264.7 cells.

RESULTS

GT1.1 cells with reduced RASSF10 expression could promote the proliferation and migration of RAW264.7 cells, and promote their expression of osteoclast markers TRAP and CK. The effect of GT1.1 cell exosomes on the RAW264.7-cell phenotype was shown to be achieved through the RASSF10-MDM2 pathway. RNA-seq allowed the identification of PI3K-AKT, MAPK, and calcium signaling as important in this regulation system of RASSF10-MDM2.

CONCLUSION

Our results indicate that GT1.1 cells activate PI3K-AKT, MAPK and calcium signaling via the RASSF10-MDM2 pathway, and promote the differentiation of RAW264.7 cells into osteoclasts through exosomes. This study may provide new ideas to aid in early diagnosis, prognostic assessment and treatment of aggressive pituitary adenomas.

How to Classify the Pituitary Neuroendocrine Tumors (PitNET)s in 2020

Adenohypophyseal tumors, which were recently renamed pituitary neuroendocrine tumors (PitNET), are mostly benign, but may present various behaviors: invasive, “aggressive” and malignant with metastases. They are classified into seven morphofunctional types and three lineages: lactotroph, somatotroph and thyrotroph (PIT1 lineage), corticotroph (TPIT lineage) or gonadotroph (SF1 lineage), null cell or immunonegative tumor and plurihormonal tumors. The WHO 2017 classification suggested that subtypes, such as male lactotroph, silent corticotroph and Crooke cell, sparsely granulated somatotroph, and silent plurihormonal PIT1 positive tumors, should be considered as “high risk” tumors. However, the prognostic impact of these subtypes and of each morphologic type remains controversial. In contrast, the French five-tiered classification, taking into account the invasion, the immuno-histochemical (IHC) type, and the proliferative markers (Ki-67 index, mitotic count, p53 positivity), has a prognostic value validated by statistical analysis in 4 independent cohorts. A standardized report for the diagnosis of pituitary tumors, integrating all these parameters, has been proposed by the European Pituitary Pathology Group (EPPG). In 2020, the pituitary pathologist must be considered as a member of the multidisciplinary pituitary team. The pathological diagnosis may help the clinician to adapt the post-operative management, including appropriate follow-up and early recognition and treatment of potentially aggressive forms.

The Past, Present, and Future Statuses of Formerly Classified "Atypical Pituitary Adenomas": A Clinicopathological Assessment of 101 Cases in a Cohort of More than 1,000 Pure Endoscopically Treated Patients in Single Center

Objective  This study was aimed to assess the clinical aggressiveness of pituitary neoplasms that were previously defined as atypical adenomas. Methods  A total of 1,042 pituitary adenomas were included in the study and 101 of them were diagnosed as atypical adenoma. Demographic characteristics, radiological evaluations, and clinical information were obtained from a computer-based patient database. Cases were categorized as atypical or typical using the criteria listed in 2004 Classification of Tumors of Endocrine Organs. Results  The cure and reoperation rates did not show any statistically significant difference between the typical and atypical adenomas. However, a higher K _i -67 labeling index was found to be associated with a higher rate of reoperation ( p  = 0.008) in atypical adenomas. Of note, cavernous sinus invasion or parasellar extension was found to be associated with lower cure rates in patients with atypical pituitary adenomas ( p  < 0.001 and p  = 0.001, respectively). Conclusion  Although atypical pituitary adenomas are known to be more invasive, this study demonstrated that the reoperation and cure rates are the same for typical and atypical adenomas. Our findings advocate for omitting the use of atypical adenoma terminology based solely on pathological evaluation. As stated in the 4th edition of the World Health Organization (WHO) classification, accurate tumor subtyping, evaluation of proliferation by means of mitotic count and K _i -67 labeling index, and radiological and intraoperative assessments of tumor invasion should be taken into consideration in the management of such neoplasms.

Pathology of prolactinomas: any predictive value?

Lactotroph adenomas, also called prolactinomas and prolactin-secreting adenomas, constitute nearly 80% of functioning pituitary tumors and about 30-50% of all adenomas in the clinical practice. Lactotroph adenomas occur in the general population at a prevalence of 45/100,000, are more common in women, but also involve men and children of both sexes. Most lactotroph adenomas are microadenomas occurring in reproductive-age women who present with oligo/amenorrhea, galactorrhea, and infertility. In men and elderly women, lactotroph adenomas are usually macroadenomas and are most commonly associated with symptoms of a tumoral mass, including headaches, neurologic defects, and visual loss. Although clinical and laboratory features may differ depending on patient's gender and age, the histopathology of the tumors is similar. Lactotroph adenomas are histologically classified into three subtypes: the common sparsely granulated lactotroph adenoma, and the rare densely granulated lactotroph adenoma and acidophilic stem cell adenoma. We will review the main pathological features of the lactotroph adenomas and some of their characteristics that may predict biological behavior and responsiveness to treatment.

Endoscopic Endonasal Transsphenoidal Surgery: History and Evolution

In previous decades, extensive and disfiguring transfacial and/or transcranial approaches were used to reach the sellar and parasellar areas. However, these surgical routes were burdened by severe complications and high mortality rates. Recently, the development of endoscopic endonasal techniques has revolutionized the surgical strategies for approaching the sella and adjacent areas and increased the development of transsphenoidal surgery. With these techniques, surgeons have been able to overcome the visual limitations of the open surgical approaches and access areas previously hidden from view. After the contributions of the Pittsburgh duo, Carrau and Jho, pioneers of pure endoscopic surgery, our school began to implement this technique, introducing technical innovations and variations, describing the anatomical details and defining new routes, and playing a key role in its widespread clinical application.

Pituitary Adenomas: What Are the Key Features? What Are the Current Treatments? Where Is the Future Taking Us?

Pituitary tumors are a heterogeneous group of lesions (usually benign) and proper understanding of the anatomy, physiology, and pathology of the hypothalamic/pituitary region is essential to make an accurate diagnosis and define the essential treatment options (i.e., surgery, medical therapies, and radiotherapy, alone or in combination). Surgery is the primary treatment for acromegaly, Cushing disease, thyroid-stimulating hormone-secreting adenomas, resistant prolactinomas, and nonfunctioning pituitary adenomas causing mass effect. Medical and radiation therapy are reserved in cases in which surgery is not possible or does not provide a complete cure. In the last decades, tremendous innovations (i.e., targeted drugs and refined surgical tools and techniques) have expanded the treatment strategies for pituitary adenomas. We herein report the current indications for and depiction of the surgical techniques in pituitary surgery, review current medical treatments, and provide a glimpse of future possibilities.

Clinicopathological analysis of 250 cases of pituitary adenoma under the new WHO classification

Pituitary adenomas (PAs) are a common subtype of intracranial tumors. The aim of the present study was to analyse the clinical and pathological features of different types of pituitary adenomas (PAs) according to the 2017 World Health Organisation Endocrine Organ Tumor Classification guidelines. The clinical data of 250 patients with PAs were collected and analysed. Differences in the incidence of invasion, recurrence and apoplexy in patients between high- and low-risk PAs were compared, as were differences in the Ki-67 index between invasive and non-invasive PAs and between recurrent PAs and non-recurrent PAs. Of the 250 cases, 45 cases were diagnosed as somatotroph adenomas, 26 cases as lactotroph adenomas, 1 case as thyrotroph adenoma, 61 cases as corticotroph adenomas, 93 cases as gonadotropin adenomas, 15 cases as null cell adenomas and 9 cases as plurihormonal adenomas. There were 5 types of high-risk pituitary adenoma identified: 17 cases of sparsely granulated somatotroph adenoma, 11 cases of lactotroph adenoma in men, 3 cases of plurihormonal PIT-1 positive adenoma and 42 cases of silent corticotroph adenoma. Crooke's cell adenoma was not identified. High-risk PAs had significantly higher rates of invasion, recurrence and apoplexy compared with that in low-risk types (P<0.001). Invasive PAs had a significantly higher Ki-67 index compared with that in non-invasive PAs (3.5±1.8 vs. 2.8±1.3; P<0.01). Recurrent PAs had a significantly higher Ki-67 index compared with that in non-recurrent PAs (3.9±1.9 vs. 2.8±1.3; P<0.001). According to the 2017 classification criteria, patients most frequently had gonadotrophin cell adenomas, followed by corticotroph adenomas and the proportion of null cell adenomas was reduced. Differences were noted in the proliferation, recurrence and apoplexy characteristics of high-risk PAs and low-risk PAs. The invasion and recurrence of PAs were found to be related to the Ki-67 index.

Prolactinomas: Prognostic Factors of Early Remission After Transsphenoidal Surgery

Background and Objective: Most patients with prolactinomas receive pharmacological treatment only, resulting in limited research on the predictors of successful prolactinoma surgery. In this study, we analyzed whether early postoperative serum prolactin concentrations and selected tumor characteristics could predict early, hormonal remission after removal of prolactinomas. Methods: We prospectively enrolled 48 consecutive patients with prolactinomas who underwent transsphenoidal resection performed by the same surgeon. Early remission, defined as a lack of hyperprolactinemia symptoms and normalization of serum prolactin concentration, was ascertained in all patients at 3 months. We evaluated the invasiveness of prolactinomas on the Knosp grading scale and measured serum prolactin concentrations on the first postoperative day. Routine immunohistochemical analysis, evaluation for plurihormonality, and assessment of the Ki-67 proliferation index (<3 or ≥3% of positive nuclei) were performed in all tumor samples. Results: Of 48 patients, 38 (79%) achieved early biochemical remission at 3 months. Patients in early remission at 3 months had lower serum prolactin concentrations on the first postoperative day than patients with recurrent or persistent hyperprolactinemia (p < 0.001). Using univariate logistic regression, larger maximum tumor diameter (p = 0.014), higher Knosp grade (p < 0.001), and plurihormonality predicted remission at 3 months (p = 0.021). However, using multivariate stepwise logistic regression, only the Knosp grade remained significant (p < 0.001). Conclusions: Radiological assessment of prolactinoma invasiveness (Knosp grades) and early postoperative serum prolactin concentrations are important predictors of early remission following transsphenoidal prolactinoma resection.

Predictive modeling for pituitary adenomas: single center experience in 501 consecutive patients

BACKGROUND

Personalized postoperative management of patients with pituitary adenomas requires an early risk stratification system.

METHODS

We reviewed 501 cases operated between 10/27/2011 and 5/5/2016 by a single neurosurgeon. We determined biochemical remission and tumor resection at 3 months, and biochemical recurrence, tumor recurrence, radiation and reoperation during follow-up. We considered age, gender, tumor diameter, cavernous sinus invasion (CSI) by MRI, diagnostic category (clinical, biochemical and immunohistochemical), and proliferation markers in a Cox proportional hazards model. We built predictive models with the significant parameters and used Kaplan-Meier survival curves for time-dependent analyses.

RESULTS

The 501 cases comprised 141 functional and 360 nonfunctional adenomas. Tumor diameter, CSI, and ki-67 index predicted long-term events. Model 1 (CSI, diameter ≥ 2.9 cm and ki-67 > 3%) identified 18 (3.6%) adenomas and predicted persistent hypersecretory syndrome and residual tumor with 98.7% specificity (OR 8.6; CI 3.0-24.7). Model 2 (ki-67 > 3% and CSI) identified 48 (9.6%) adenomas and had 93.1% specificity (OR 3.3; CI 1.8-6.0). Model 3 (ki-67 > 3%, mitoses and p53, former "atypical" adenoma) identified 26 (5.2%) adenomas and had 96.0% specificity (OR 2.3; CI 1.0-5.0). Model 1 best predicted the long-term event-free survival and was strengthened when Knosp 3-4 CSI grades were used. Model 2 better identified the smaller adenomas at risk. Among the WHO 2017 special PA subtypes, patients with silent corticotroph adenoma had a lower event-free survival than ACTH-negative nonfunctional adenomas.

CONCLUSION

Use of CSI, ki-67 and tumor diameter in prediction models facilitates tailored surveillance and management of patients with pituitary adenomas.

Prediction of high proliferative index in pituitary macroadenomas using MRI-based radiomics and machine learning

PURPOSE

Pituitary adenomas are among the most frequent intracranial tumors. They may exhibit clinically aggressive behavior, with recurrent disease and resistance to multimodal therapy. The ki-67 labeling index represents a proliferative marker which correlates with pituitary adenoma aggressiveness. Aim of our study was to assess the accuracy of machine learning analysis of texture-derived parameters from pituitary adenomas preoperative MRI for the prediction of ki-67 proliferation index class.

METHODS

A total of 89 patients who underwent an endoscopic endonasal procedure for pituitary adenoma removal with available ki-67 labeling index were included. From T2w MR images, 1128 quantitative imaging features were extracted. To select the most informative features, different supervised feature selection methods were employed. Subsequently, a k-nearest neighbors (k-NN) classifier was employed to predict macroadenoma high or low proliferation index. Algorithm validation was performed with a train-test approach.

RESULTS

Of the 12 subsets derived from feature selection, the best performing one was constituted by the 4 highest correlating parameters at Pearson's test. These all showed very good (ICC ≥ 0.85) inter-observer reproducibility. The overall accuracy of the k-NN in the test group was of 91.67% (33/36) of correctly classified patients.

CONCLUSIONS

Machine learning analysis of texture-derived parameters from preoperative T2 MRI has proven to be effective for the prediction of pituitary macroadenomas ki-67 proliferation index class. This might aid the surgical strategy making a more accurate preoperative lesion classification and allow for a more focused and cost-effective follow-up and long-term management.

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.

Pituitary carcinomas: review of the current literature and report of atypical case

Introduction: Pituitary carcinomas are poorly understood, rare entities. They are distinguished from adenomas not by histopathological features but rather by the presence of metastases.Objective: We discuss the diagnosis, mechanism of dissemination and pathogenesis based on a review of the literature and illustrated by a singular case.Case Report: A 59-year-old male presented with a dural-based posterior fossa lesion. He had been diagnosed with a pituitary chromophobe adenoma 43 years earlier that was treated at the time with surgery and radiation therapy. A presumptive diagnosis of a radiation-induced meningioma was made and surgery was recommended. At surgery the tumour resembled a pituitary adenoma. Histopathology, laboratory findings, and the patient's medical history confirmed the final diagnosis of a prolactin-secreting pituitary carcinoma. To our knowledge, this is the longest reported interval between the pituitary adenoma and metastatic lesion diagnosis (43 years).Conclusion: Management should be tailored to individual patient and may include a combination of treatments (surgery, radiation therapy, chemotherapy, and hormone-targeted therapy). Functionally active tumours may be monitored with hormone levels as tumour markers.

The Prognostic Roles of the Ki-67 Proliferation Index, P53 Expression, Mitotic Index, and Radiological Tumor Invasion in Pituitary Adenomas

The fourth edition of the World Health Organization (WHO) classification of pituitary tumors recommended evaluation of tumor proliferation and invasion to identify aggressiveness. We aimed to assess the prognostic roles of the Ki-67 proliferation index, mitotic index, P53 expression, and cavernous sinus invasion in pituitary adenomas (PAs). Among the 601 patients who underwent transnasal/transsphenoidal adenomectomy from 2001 to 2016, 101 patients (16.8%) who had tumors with a high (≥ 3%) Ki-67 index (group A) and a control group consisting of 43 patients with a low (< 3%) Ki 67 index who were matched for age, gender, and tumor type were included. Mitotic index and P53 expressions were evaluated. Patient characteristics, histopathology reports, pre/postoperative magnetic resonance imaging (MRI), and follow-up data were assessed retrospectively. The frequency of macroadenomas and mean tumor size were greater in group A when compared to group B (67.4 vs. 94.1%, p< 0.01 and 25 ± 10.6 vs. 18 ± 11 mm, p< 0.01, respectively). Invasion to cavernous sinus was found in 53 (36.8%) patients and was more frequent in group A (p<0.01). The mean number of surgery was higher in group A than group B (p< 0.05). The mean follow-up period was 46.6 ± 34 months. The postoperative MRIs and follow-up data for at least 24 months were available in 117 patients. Recurrence risk was higher in group A than group B (p = 0.03). Tumors with high Ki-67 proliferation index were grouped as 3-5, 6-10, 11-15, and > 15%. The risk of recurrence was not different between groups of high Ki-67 index. The optimal cutoff point of the Ki-67 proliferation index that predicted recurrence was 2.5% with 84.6% sensitivity and 47.4% specificity. The cavernous sinus invasion on MRI was associated with recurrence (p = 0.03). Tumor size and recurrence risk were not associated with P53 expression. High P53 expression was related with cavernous sinus invasion (p = 0.03). The mitotic index was not associated with recurrence risk and tumor invasion. Recurrence risk was higher in tumors with ≥ 2 histopathological atypia criteria (p = 0.01). High Ki-67 index with a 2.5% cutoff point and cavernous sinus invasion on MRI are reliable markers for predicting recurrence in PAs. Recurrence risk is also higher in tumors with two histopathological aggressiveness criteria. Strict follow-up and more aggressive treatment approaches may be necessary for invasive-proliferative PAs.

Highly Aggressive and Radiation-Resistant, "Atypical" and Silent Pituitary Corticotrophic Carcinoma: A Case Report and Review of the Literature

Background

Pituitary tumors typically remain silent unless interaction with nearby structures occurs. Rare subsets of pituitary tumors display aggressive phenotypes: highly mitotic, locally invasive, metastatic, chemotherapy and radiation resistant, etc. Disease progression and response to therapy is ill-defined in these subtypes, and their true prognostic potential is debated. Thus, identifying tumor characteristics with prognostic value and efficacious treatment options remains a challenge in aggressive pituitary tumors.

Case Presentation

A 45-year-old female presented with a nonfunctioning corticotropic pituitary macroadenoma with biomarkers suggestive of an “atypical” subtype: Ki-67 of 8–12%, increased mitosis, and locally invasive. Despite resections and radiation, growth continued, eventually affecting her vision. Although histologically ACTH positive, the patient remained clinically asymptomatic. Twelve months later, an episode of Cushing's disease-induced psychosis prompted a PET-CT scan, identifying sites of metastasis. Temozolomide was added to her medical regimen, and her metastatic liver lesions and boney metastases were treated with radiofrequency ablation and stereotactic body radiation therapy, respectively. Systemic treatment resulted in a drop in her ACTH levels, with her most recent scans/labs at 12 months following RFA suggesting remission.

Conclusions

This is a unique presentation of a pituitary tumor, displaying characteristics of both clinically silent corticotropic and “atypical” macroadenoma subtypes. Although initially ACTH positive while clinically silent, the patient's disease ultimately recurred metastatically with manifestations of Cushing's disease and psychosis. With the addition of temozolomide to her treatment plan, her primary and metastatic sites have responded favorably to radiation therapy. Thus, the addition of temozolomide may be beneficial in the treatment of aggressive pituitary tumors.

Study of Simple Immunohistochemical Cytocolorimetric Assay Application for More Accurate Assessment of Prognosis in Patients with Pituitary Adenomas

BACKGROUND

Immunohistochemistry is a basic diagnostic technique. Immunohistochemical examination results reflect mainly qualitative and less quantitative characteristics of proteomic status of cells. A combined approach with complex quantitative evaluation of marker expression using colorimetric analysis and computer technologies can expand the diagnostic capabilities of immunohistochemistry. We studied such an approach developed by using expression of the proliferative marker Ki-67 in pituitary adenomas.

METHODS

A retrospective, blind, randomized, comparative study was performed of Ki-67 expression activity in pituitary adenomas using the traditional Ki-67 labeling index and a simple immunohistochemical cytocolorimetric analysis developed by us with immunohistochemical cytocolorimetric index (ICI) estimation as predictors of relapse, assessing the relationships of these indicators with the time before relapse.

RESULTS

Mean Ki-67 labeling index was 3.87% ± 0.29% in the relapse-free group and 4.01% ± 0.29% in the relapse group; the difference was not statistically significant. The average Ki-67 ICI was 24.16% ± 0.51% in the relapse-free group and 30.68% ± 0.64% in the relapse group; the difference was statistically significant. The correlation coefficient of ICI values and time before relapse was -0.302, indicating the presence of a weak negative correlation.

CONCLUSIONS

We successfully tested an ICI estimation method developed by us to assess Ki-67 expression in pituitary adenomas. The ICI technique can be used both as a prognostic factor for relapse and, in combination with other modern proteomic and genetic methods, as the basis for creation of new multimodal analyzing systems for functional state assessment of cells and tissues.

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.

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.

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.

Management of nonfunctioning pituitary tumors: radiotherapy

External beam radiotherapy (RT) is an essential part of the management of intracranial tumors and has been used in treating pituitary adenomas for more than five decades. It has been demonstrated that conventional RT for postoperative residual or progressive nonfunctioning pituitary adenomas (NFAs) present an excellent long-term local tumor control, although its use has been limited because of the potential late toxicity related to radiation treatments. Recent advances in radiation techniques have led to more accurate treatments, rendering obsolete many commonly held views of the "old" radiotherapy. New techniques include intensity modulated radiotherapy, volumetric-modulated arc therapy, and stereotactic techniques, either stereotactic radiosurgery or fractionated stereotactic radiotherapy. New techniques allow the delivering of higher radiation doses to the target with rapid dose fall-off in the surrounding normal tissues, and potentially limiting the long term toxicity of radiation. In this review, we present a critical analysis of the most recent available literature on the use of radiation in patients with NFAs, focusing particularly on the efficacy and safety of radiation stereotactic techniques.

Atypical pituitary adenoma: a clinicopathologic case series

OBJECTIVE In 2004, the WHO classified atypical pituitary adenoma as a distinct adenoma subtype. However, the clinical significance of this distinction remains undetermined. The authors sought to define patient characteristics, tumor features, and treatment outcomes associated with atypical pituitary adenoma. METHODS The authors reviewed records of patients who underwent resection of pituitary adenoma at the University of California, San Francisco, between 2007 and 2014. Per institutional protocol, adenomas exhibiting mitotic activity underwent evaluation for all 3 markers of atypicality (mitotic index, extensive p53 staining, and MIB-1 index ≥ 3%). Statistical analyses were performed using χ2, Fisher's exact test, t-test, log-rank, and logistic regression. RESULTS Between 2007 and 2014, 701 patients underwent resection for pituitary adenoma. Among these patients, 122 adenomas exhibited mitotic activity and therefore were evaluated for all 3 markers of atypicality, with 36 tumors (5%) proving to be atypical. There were 21 female patients (58%) and 15 male patients (42%) in the atypical cohort, and 313 female patients (47%) and 352 male patients (53%) in the nonatypical cohort (p = 0.231). The mean age of patients in the atypical cohort was 37 years (range 10-65 years), which was significantly lower than the mean age of 49 years (range 10-93 years) for patients in the nonatypical cohort (p < 0.001). The most common presenting symptoms for patients with atypical adenomas were headaches (42%) and visual changes (33%). Atypical adenomas were more likely to be functional (78%) than nonatypical adenomas (42%; p < 0.001). Functional atypical adenomas were significantly larger than functional nonatypical adenomas (mean diameter 2.2 vs 1.4 cm; p = 0.009), as were nonfunctional atypical adenomas compared with nonfunctional nonatypical adenomas (mean diameter 3.3 vs 2.3 cm; p = 0.01). Among the entire adenoma cohort, larger presenting tumor size was associated with cavernous sinus invasion (p < 0.001), and subtotal resection was associated with cavernous sinus invasion (p < 0.001) and larger size (p < 0.001) on binomial multivariate regression. The median time until recurrence was 56 months for atypical adenomas, 129 months for functional nonatypical adenomas, and 204 months for nonfunctional nonatypical adenomas (p < 0.001). Functional atypical adenomas recurred more frequently and significantly earlier than functional nonatypical adenomas (p < 0.001). When accounting for extent of resection, cavernous sinus invasion, size, age, sex, and functional subtype, atypicality remained a significant predictor of earlier recurrence among functional adenomas (p = 0.002). CONCLUSIONS When compared with nonatypical pituitary adenomas, atypical adenomas are more likely to present in younger patients at a larger size, are more often hormonally hypersecretory, and are associated with earlier recurrence. These features lend credence to atypical pituitary adenomas being a distinct clinical entity in addition to a discrete pathological diagnosis.

Management of NFAs: medical treatment

INTRODUCTION

Non-functioning pituitary adenomas (NFPAs) are in general large tumors that present with symptoms secondary to local pressure on adjacent structures. Transsphenoidal surgery is the first line of treatment but residual tumor mass is often detected post-operatively. Medical therapy, in any stage of tumor management, is not well established.

METHODS

A literature search was performed to review the available data on medical treatment of NFPAs.

RESULTS

Medications investigated for the treatment of NFPAs include dopamine receptor agonists (DA) and somatostatin receptor ligands. Randomized controlled trials are lacking, but available data suggest that DA have a positive effect on tumor remnant stabilization after surgery and could be considered in this setting. Temozolomide is reserved for aggressive tumors, although future studies are required.

CONCLUSIONS

NFPA are often not amenable to complete surgical resection. Conservative follow-up after surgery is associated with a high prevalence of tumor remnant progression. DA therapy may prevent residual tumor enlargement in over 85% of these patients, with a substantial consequent reduction in the need for repeat surgery or radiation therapy. It is our view that DA treatment should be routinely considered for the management of NFPA patients with incompletely resected tumors.

Variability and Lack of Prognostic Value Associated With Atypical Pituitary Adenoma Diagnosis: A Systematic Review and Critical Assessment of the Diagnostic Criteria

BACKGROUND

Atypical pituitary adenomas (APAs) are a subset of pituitary adenomas (PAs) characterized by the 2004 World Health Organization (WHO) guidelines to have higher risk histopathological features than typical PAs. In July 2017, the WHO published an update to their classification of pituitary tumors and abandoned the APA terminology.

OBJECTIVE

To assess the prevalence and outcomes of patients diagnosed with APA through a literature review. Focus was placed on variation in the application of the previous WHO criteria and on rates of recurrence.

METHODS

A systematic review of PubMed (2004-July 2017) was performed to identify studies reporting prevalence and clinical characteristics/outcomes of APA. Eight studies were analyzed for prevalence. Six studies reporting histopathological details were analyzed in depth.

RESULTS

Of the 7105 included patients, 373 (5.2%) met criteria for APA (prevalence range: 3%-15%). Only 2 of 8 studies utilized identical grading criteria, demonstrating a lack of standardized application. Most APAs (84%) were macroadenomas, with 52% invasive on magnetic resonance imaging. Nonfunctional PAs were most common (37%), followed by prolactinomas (23%) and Growth Hormone adenomas (21%). Recurrence/progression occurred in 21% of APA patients (follow-up range 37-75 mo). Only 2 of 8 studies reported an association between APA diagnosis and recurrence/progression.

CONCLUSION

Based on diagnostic variability and lack of association with clinical outcomes, refinement of criteria for APA was necessary. The WHO update eliminates the ambiguity in APA diagnosis in favor of criteria that emphasize clinical behavior (invasion, recurrence, and resistance to treatment) and molecular markers. Our review supports abandonment of the previous APA designation due to limited prognostic utility.

Implications of the World Health Organization definition of atypia on surgically treated functional and non-functional pituitary adenomas

BACKGROUND

The World Health Organization (WHO) defines atypical pituitary adenomas as tumours with a MIB-1 labelling index ≥3%, p53 positivity and increased mitotic activity. Although a few reports have described the clinical and radiological correlates of atypia in pituitary adenomas, its impact on postoperative outcomes is not clearly defined.

METHOD

We reviewed preoperative and postoperative records of patients undergoing surgery for pituitary adenomas. Postoperative outcomes for functional adenomas (FPAs) were assessed according to contemporary definitions of remission and recurrence. For non-functional pituitary adenomas (NFPAs), extent of resection and disease progression were defined on the basis of postoperative magnetic resonance imaging.

RESULTS

Of 394 patients included for analysis, 29 cases (7.4%) fulfilled criteria for atypia. Patients with atypical tumours were significantly younger than those with typical adenomas. Remission was possible in 47.4% of FPAs, and was unrelated to the presence of atypia. In NFPAs, local invasiveness was negatively associated with extent of resection (OR, 0.255; 95% CI, 0.086-0.753; p < 0.001). In 93 NFPAs followed postoperatively with serial imaging over a mean duration of 37.5 months, disease progression/recurrence was significantly associated with the presence of atypia (OR, 5.058; 95% CI, 1.273-20.098; p = 0.021) on multivariate analysis.

CONCLUSIONS

Patients with atypical non-functional pituitary adenomas are at risk for postoperative recurrence and disease progression, suggesting a need for adjuvant therapy. However, only a small fraction of pituitary tumours demonstrate atypia, as defined by the WHO, limiting its clinical utility.

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.

Risk of Recurrence in Pituitary Neuroendocrine Tumors: A Prospective Study Using a Five-Tiered Classification

BACKGROUND

Most pituitary neuroendocrine tumors (PitNETs) show benign behavior, but a substantial number are invasive, recur, or resist medical treatment. Based on a retrospective case-control study, we recently proposed a classification of PitNETs of prognostic relevance. This prospective study aims to test the value of this classification in an independent patient cohort.

METHODS

All patients who underwent PitNET surgery from 2007 to 2012 in one single center were included. Using a grading system based on invasion on magnetic resonance imaging, immunocytochemical profile, Ki-67, mitotic index, and p53 positivity, tumors were classified. Progression-free survival of the graded tumors was calculated by the Kaplan-Meier method and compared using the log-rank test. A multivariate analysis, using a Cox regression model, was also performed.

RESULTS

In total, 365 patients had grade 1a PitNETs (51.2%), followed by grade 2a (32.3%), 2b (8.8%), and 1b tumors (7.7%). Of 213 patients with a follow-up, 42% had recurrent (n = 52) or progressive disease (n = 37) at 3.5 years. Grade was a significant predictor of progression-free survival (P < 0.001). Multivariate analysis indicated grade (P < 0.001), age (P = 0.035), and tumor type (P = 0.028) as independent predictors of recurrence and/progression. This risk was 3.72-fold higher for a grade 2b tumor compared with grade 1a tumor.

CONCLUSIONS

Our data suggest that classification of PitNETs into five grades is of prognostic value to predict postoperative tumor behavior and identifies patients who have a high risk of early recurrence or progression. It therefore will allow clinicians to adapt their therapeutic strategies and stratify patients in future clinical trials.

Younger age is a risk factor for regrowth and recurrence of nonfunctioning pituitary macroadenomas: Results from a single Australian centre

OBJECTIVE

The natural history of nonfunctioning pituitary macroadenomas (NFPMA) after surgical resection is variable, with guidelines unable to define the duration of radiological follow-up. In this first Australian series, we identify risk factors for regrowth/recurrence of NFPMA to assist with guiding recommendations for long-term follow-up.

DESIGN

Retrospective analysis of all radiotherapy-naïve cases with NFPMA resected between 1995 and 2013.

PATIENTS

One hundred and twenty-three cases had both ≥2 postoperative scans and ≥12-month follow-up.

MEASUREMENTS

Regrowth was defined as any sustained increase in diameter of residual adenoma or recurrence as any new adenoma occurring post complete resection on serial pituitary MRI.

RESULTS

Median follow-up time was 48 months (interquartile range [IQR]: 31-86). Overall regrowth/recurrence occurred in 29% (36/123). Regrowth occurred in 40% (30/76) at a median time of 44.5 months (IQR 22-80) compared to recurrence of 12.5% (6/48; P=.003), occurring at a median time of 48 months (IQR 12-96; P=.7). Further treatment was required in 66.7% and 56.7%, respectively (=1.0). Risk factors for regrowth/recurrence by multivariate analysis were presence of residual disease and younger age at presentation. The longest time for regrowth was 168 months (14 years) and recurrence 156 months (13 years).

CONCLUSIONS

Presence of postoperative residual adenoma and younger age at presentation are the main predictors of regrowth/recurrence in NFPMA. Long-term serial imaging is required to detect regrowth and recurrence in younger patients and those with residual disease. Most regrowth/recurrences will occur within 10 years of follow-up.

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.

Molecular targeted therapies in adrenal, pituitary and parathyroid malignancies

Tumourigenesis is a relatively common event in endocrine tissues. Currently, specific guidelines have been developed for common malignant endocrine tumours, which also incorporate advances in molecular targeted therapies (MTT), as in thyroid cancer and in gastrointestinal neuroendocrine malignancies. However, there is little information regarding the role and efficacy of MTT in the relatively rare malignant endocrine tumours mainly involving the adrenal medulla, adrenal cortex, pituitary, and parathyroid glands. Due to the rarity of these tumours and the lack of prospective studies, current guidelines are mostly based on retrospective data derived from surgical, locoregional and ablative therapies, and studies with systemic chemotherapy. In addition, in many of these malignancies the prognosis remains poor with individual patients responding differently to currently available treatments, necessitating the development of new personalised therapeutic strategies. Recently, major advances in the molecular understanding of endocrine tumours based on genomic, epigenomic, and transcriptome analysis have emerged, resulting in new insights into their pathogenesis and molecular pathology. This in turn has led to the use of novel MTTs in increasing numbers of patients. In this review, we aim to present currently existing and evolving data using MTT in the treatment of adrenal, pituitary and malignant parathyroid tumours, and explore the current utility and effectiveness of such therapies and their future evolution.