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

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.

[Efficacy of standard methods in the treatment of prolactin-secreting pituitary carcinoma]

Pituitary carcinoma (metastatic neuroendocrine tumor of the pituitary gland) is the pituitary tumor with confirmed craniospinal and/or systemic metastases. These tumors are extremely rare accounting for only 0.1% to 0.5% of all pituitary tumours and are characterized by high mortality. In the presented case, pituitary carcinoma with intracranial metastasis was diagnosed in a young patient 25 years after manifestation of an aggressive recurrent prolactin-secreting pituitary tumor. Standard therapy (removal of metastasis, radiation therapy, cabergoline therapy) resulted in a long-term remission of the disease.

Clinical features of pituitary carcinoma: analysis based on a case report and literature review

Introduction

Pituitary carcinoma (PC) is an extremely rare tumor of the adenohypophysis, which manifests as craniospinal dissemination and/or systemic metastasis. The diagnosis of PC is particularly difficult, as the clinical diagnosis only can be made after the metastasis is found. Owing to the complex diagnostic process and less effective treatments, the clinical prognosis of PC is usually very poor. Hence, it is of great significance to illustrate the diagnosis and treatment course of PC.

Methods

In this case report, we described a 48-year-old male patient who was diagnosed with pituitary adenoma (PA) initially and then was diagnosed with PC eventually after spinal cord metastasis was found, and we illustrated the treatment course as well. Furthermore, we summarized all the published case reports until now and provided a comprehensive review of the diagnosis, treatment, prediction, and clinical outcome of PC.

Results and Conclusions

We found that most PC patients had adrenocorticotropic hormone/prolactin (ACTH/PRL)-secreting tumors, Ki-67 ≥ 10%, and P53 positivity, which may have the potential to predict the transformation from PA to PC; surgery excision combined with temozolomide (TMZ) and radiotherapy is helpful to prolong the survival of PC patients.

Silent Corticotroph Adenomas Demonstrate Predilection for Sphenoid Sinus, Cavernous Sinus, and Clival Invasion Compared with Other Subtypes

BACKGROUND

Nonfunctional pituitary neuroendocrine tumors (PitNETs) exhibit wide variability in growth pattern based on subtype. Silent corticotroph adenomas (SCAs) demonstrate aggressive growth compared with other nonfunctional pituitary adenomas (NFPAs), especially into the cavernous sinus. In this study, we sought to characterize other growth patterns of SCAs compared with NFPAs.

METHODS

We performed a retrospective analysis of all patients with nonfunctional PitNETs treated with surgical resection via endoscopic endonasal approach at a single institution from August 1, 2018, to May 11, 2024. Preoperative computed tomography and magnetic resonance imaging were reviewed to determine extension into the suprasellar space, sphenoid sinus, cavernous sinus, and clivus.

RESULTS

The study comprised 91 patients, including 20 SCAs and 71 NFPAs. SCAs demonstrated significantly greater rates of growth into the sphenoid sinus (55.0% vs. 23.94%, P = 0.013), clivus (65.0% vs. 16.9%, P < 0.0001), and cavernous sinus (defined as Knosp grade 3 or 4; 55.0% vs. 23.35%, P = 0.016). Other NFPAs were more likely to grow into the suprasellar space (92.96% vs. 75.0%, P = 0.038). Tumor volume was similar between groups (11.93 cm3 vs. 9.06 cm3, P = 0.2).

CONCLUSIONS

Silent corticotroph PitNETs demonstrate predilection for invasion of bony structures, with higher rates of growing through the sellar floor into the sphenoid sinus, growing posteroinferiorly into the clivus and laterally into the cavernous sinuses. Other nonfunctional PitNETs tended to follow the path of least resistance, growing superiorly into the suprasellar space. These differences in growth patterns may account for some of the clinical challenges of treating silent corticotroph PitNETs.

Clinical application of reserved gastric tube in neuroendoscopic endonasal surgery for pituitary tumor

BACKGROUND

The neuroendoscopic approach has the advantages of a clear operative field, convenient tumor removal, and less damage, and is the development direction of modern neurosurgery. At present, transnasal surgery for sphenoidal pituitary tumor is widely used. But it has been found in clinical practice that some patients with this type of surgery may experience post-operative nausea and vomiting and other discomforts.

AIM

To explore the effect of reserved gastric tube application in the neuroendoscopic endonasal resection of pituitary tumors.

METHODS

A total of 60 patients who underwent pituitary adenoma resection via the endoscopic endonasal approach were selected and randomly divided into the experimental and control groups, with 30 in each group. Experimental group: After anesthesia, a gastric tube was placed through the mouth under direct vision using a visual laryngoscope, and the fluid accumulated in the oropharynx was suctioned intermittently with low negative pressure throughout the whole process after nasal disinfection, during the operation, and when the patient recovered from anesthesia. Control group: Given the routine intraoperative care, no gastric tube was left. The number of cases of nausea/vomiting/aspiration within 24 h post-operation was counted and compared between the two groups; the scores of pharyngalgia after waking up, 6 h post-operation, and 24 h post-operation. The frequency of postoperative cerebrospinal fluid leakage and intracranial infection were compared. The hospitalization days of the two groups were statistically compared.

RESULTS

The times of postoperative nausea and vomiting in the experimental group were lower than that in the control group, and the difference in the incidence of nausea was statistically significant (P < 0.05). After the patient woke up, the scores of sore throat 6 h after the operation and 24 h after operation were lower than those in the control group, and the difference was statistically significant (P < 0.05). The number of cases of postoperative cerebrospinal fluid leakage and intracranial infection was higher than that of the control group, but there was no statistically significant difference from the control group (P > 0.05). The hospitalization days of the experimental group was lower than that of the control group, and the difference was statistically significant (P < 0.05).

CONCLUSION

Reserving a gastric tube in the endoscopic endonasal resection of pituitary tumors, combined with intraoperative and postoperative gastrointestinal decompression, can effectively reduce the incidence of nausea, reduce the number of vomiting and aspiration in patients, and reduce the complications of sore throat The incidence rate shortened the hospitalization days of the patients.

Neuro-ophthalmological findings of pituitary metastasis: Case series from a single center and review of the literature

When pituitary metastasis (PM) invades the pituitary gland, it leads to impaired endocrine function and compression and infiltration of surrounding tissues, causing a series of clinical alterations. We presented seven patients with PM evaluated at neuro-ophthalmologic clinic and reviewed neuro-ophthalmological findings of 44 cases with PM in the English literature from 1979 to December 2022. The mean age at diagnosis was 58.1 years, and 45.1% were male. The mean latency period from primary cancer to the diagnosis of PM was 57.6 months. PM is the only presenting sign of malignancy in 11.8% of patients. The mean time from the visual disturbance to the diagnosis of PM was 96.3 days. Visual acuity decreased in 72.5% and 60.8% of cases with visual field defects. 74.2% exhibited a pattern of temporal field defect respecting the vertical meridian. Isolated ophthalmoplegia was found in 37.3% of patients. The most common ocular motor nerve palsy was unilateral III nerve palsy. Breast cancer was the most common primary malignancy. 84.6% entirely or partially relieved the neuro-ophthalmic symptoms after treatment. 51% of patients were alive during a mean follow-up period of 11 months. The mean survival duration was within six months in 65% of deceased patients. For elderly patients with a pituitary tumor, PM should be on the list of differential diagnoses for those with visual impairment, especially ocular motor nerve palsy, even if diabetic insipidus is not present, with or even without a history of malignancy, regardless of the primary tumor site.

Metastatic pituitary tumors: an institutional case series

PURPOSE

Pituitary carcinomas are a rare entity that respond poorly to multimodal therapy. Patients follow a variable disease course that remains ill-defined.

METHODS

We present an institutional case series of patients treated for pituitary carcinomas over a 30-year period from 1992 to 2022. A systematic review was conducted to identify prior case series of patients with pituitary carcinomas.

RESULTS

Fourteen patients with a mean age at pituitary carcinoma diagnosis of 52.5 years (standard deviation [SD] 19.4) met inclusion criteria. All 14 patients had tumor subtypes confirmed by immunohistochemistry and hormone testing, with the most common being ACTH-producing pituitary adenomas (n = 12). Patients had a median progression-free survival (PFS) of 1.4 years (range 0.7-10.0) and a median overall survival (OS) of 8.4 years (range 2.3-24.0) from pituitary adenoma diagnosis. Median PFS and OS were 0.6 years (range 0.0-2.2) and 1.5 years (range 0.1-9.6) respectively upon development of metastases. Most patients (n = 12) had locally invasive disease to the cavernous sinus, dorsum sellae dura, or sphenoid sinus prior to metastasis. Common sites of metastasis included the central nervous system, liver, lung, and bone. In a pooled analysis including additional cases from the literature, treatment of metastases with chemotherapy or a combination of radiation therapy and chemotherapy significantly prolonged PFS (p = 0.02), while failing to significantly improve OS (p = 0.14).

CONCLUSION

Pituitary carcinomas are highly recurrent, heterogenous tumors with variable responses to treatment. Multidisciplinary management with an experienced neuro-endocrine and neuro-oncology team is needed given the unrelenting nature of this disease.

Aggressive Pituitary Tumors and Pituitary Carcinomas: From Pathology to Treatment

Aggressive pituitary tumors (APTs) and pituitary carcinomas (PCs) are heterogeneous with regard to clinical presentation, proliferative markers, clinical course, and response to therapy. Half of them show an aggressive course only many years after the first apparently benign presentation. APTs and PCs share several properties, but a Ki67 index greater than or equal to 10% and extensive p53 expression are more prevalent in PCs. Mutations in TP53 and ATRX are the most common genetic alterations; their detection might be of value for early identification of aggressiveness. Treatment requires a multimodal approach including surgery, radiotherapy, and drugs. Temozolomide is the recommended first-line chemotherapy, with response rates of about 40%. Immune checkpoint inhibitors have emerged as second-line treatment in PCs, with currently no evidence for a superior effect of dual therapy compared to monotherapy with PD-1 blockers. Bevacizumab has resulted in partial response (PR) in few patients; tyrosine kinase inhibitors and everolimus have generally not been useful. The effect of peptide receptor radionuclide therapy is limited as well. Management of APT/PC is challenging and should be discussed within an expert team with consideration of clinical and pathological findings, age, and general condition of the patient. Considering that APT/PCs are rare, new therapies should preferably be evaluated in shared standardized protocols. Prognostic and predictive markers to guide treatment decisions are needed and are the scope of ongoing research.

An update on, and genetics of refractory adenomas of childhood

Pituitary adenomas in childhood tend to be more frequently due to germline genetic changes and are often diagnosed at late stages due to delayed recognition by pediatricians and other caretakers who are not familiar with this rare disease in childhood. As a result, often, pediatric pituitary adenomas are aggressive or remain refractory to treatment. In this review, we discuss germline genetic defects that account for the most common pediatric pituitary adenomas that are refractory to treatment. We also discuss some somatic genetic events, such as chromosomal copy number changes that characterize some of the most aggressive pituitary adenomas in childhood that end up being refractory to treatment.

Recent Therapeutic Advances in Pituitary Carcinoma

Pituitary carcinoma (PC) is a rare, aggressive malignancy that comprises 0.1-0.2% of all pituitary tumors. PC is defined anatomically as a pituitary tumor that metastasizes outside the primary intrasellar location as noncontiguous lesions in the central nervous system or as metastases to other organs. Similar to pituitary adenoma, PC originates from various cell types of the pituitary gland and can be functioning or nonfunctioning, with the former constituting the majority of the cases. Compression of intricate skull-based structures, excessive hormonal secretion, impaired pituitary function from therapy, and systemic metastases lead to debilitating symptoms and a poor survival outcome in most cases. PC frequently recurs despite multimodality treatments, including surgical resection, radiotherapy, and biochemical and cytotoxic treatments. There is an unmet need to better understand the pathogenesis and molecular characterization of PC to improve therapeutic strategies. As our understanding of the role of signaling pathways in the tumorigenesis of and malignant transformation of PC evolves, efforts have focused on targeted therapy. In addition, recent advances in the use of immune checkpoint inhibitors to treat various solid cancers have led to an interest in exploring the role of immunotherapy for the treatment of aggressive refractory pituitary tumors. Here, we review our current understanding of the pathogenesis, molecular characterization, and treatment of PC. Particular attention is given to emerging treatment options, including targeted therapy, immunotherapy, and peptide receptor radionuclide therapy.

The hallmarks of cancer… in pituitary tumors?

Over 20 years ago, Hanahan and Weinberg published a seminal review that addressed the biological processes that underly malignant transformation. This classical review, along with two revisions published in 2011 and 2022, has remain a classic of the oncology literature. Since many of the addressed biological processes may apply to non-malignant tumorigenesis, we evaluated to what extent these hallmarks pertain to the development of pituitary adenomas.Some of the biological processes analyzed in this review include genome instability generated by somatic USP8 and GNAS mutations in Cushing's diseases and acromegaly respectively; non-mutational epigenetic reprograming through changes in methylation; induction of angiogenesis through alterations of VEGF gene expression; promotion of proliferative signals mediated by EGFR; evasion of growth suppression by disrupting cyclin dependent kinase inhibitors; avoidance of immune destruction; and the promotion of inflammation mediated by alteration of gene expression of immune check points. We also elaborate further on the existence of oncogene induced senescence in pituitary tumors. We conclude that a better understanding of these processes can help us dilucidated why pituitary tumors are so resistant to malignant transformation and can potentially contribute to the development of novel anticancer treatments.

Pituitary carcinoma: A cytopathologic dilemma when metastatic to cervical lymph nodes

Pituitary carcinomas are rare tumors defined by distant metastasis or cerebrospinal spread. The morphologic features are poorly characterized because only a handful of reports have been described by fine-needle aspiration cytology. We present a case of pituitary carcinoma diagnosed in a 64-year-old male and highlight this rare entity's key cytomorphologic features and differential diagnosis.

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.

Clinical Biology of the Pituitary Adenoma

All endocrine glands are susceptible to neoplastic growth, yet the health consequences of these neoplasms differ between endocrine tissues. Pituitary neoplasms are highly prevalent and overwhelmingly benign, exhibiting a spectrum of diverse behaviors and impact on health. To understand the clinical biology of these common yet often innocuous neoplasms, we review pituitary physiology and adenoma epidemiology, pathophysiology, behavior, and clinical consequences. The anterior pituitary develops in response to a range of complex brain signals integrating with intrinsic ectodermal cell transcriptional events that together determine gland growth, cell type differentiation, and hormonal production, in turn maintaining optimal endocrine health. Pituitary adenomas occur in 10% of the population; however, the overwhelming majority remain harmless during life. Triggered by somatic or germline mutations, disease-causing adenomas manifest pathogenic mechanisms that disrupt intrapituitary signaling to promote benign cell proliferation associated with chromosomal instability. Cellular senescence acts as a mechanistic buffer protecting against malignant transformation, an extremely rare event. It is estimated that fewer than one-thousandth of all pituitary adenomas cause clinically significant disease. Adenomas variably and adversely affect morbidity and mortality depending on cell type, hormone secretory activity, and growth behavior. For most clinically apparent adenomas, multimodal therapy controlling hormone secretion and adenoma growth lead to improved quality of life and normalized mortality. The clinical biology of pituitary adenomas, and particularly their benign nature, stands in marked contrast to other tumors of the endocrine system, such as thyroid and neuroendocrine tumors.

Aggressive pituitary tumours and carcinomas, characteristics and management of 171 patients

OBJECTIVE

To describe clinical and pathological characteristics and treatment outcomes in a large cohort of aggressive pituitary tumours (APT)/pituitary carcinomas (PC).

DESIGN

Electronic survey August 2020-May 2021.

RESULTS

96% of 171 (121 APT, 50 PC), initially presented as macro/giant tumours, 6 were microadenomas (5 corticotroph). Ninety-seven tumours, initially considered clinically benign, demonstrated aggressive behaviour after 5.5 years (IQR: 2.8-12). Of the patients, 63% were men. Adrenocorticotrophic hormone (ACTH)-secreting tumours constituted 30% of the APT/PC, and the gonadotroph subtypes were under-represented. Five out of 13 silent corticotroph tumours and 2/6 silent somatotroph tumours became secreting. Metastases were observed after median 6.3 years (IQR 3.7-12.1) from diagnosis. At the first surgery, the Ki67 index was ≥3% in 74/93 (80%) and ≥10% in 38/93 (41%) tumours. An absolute increase of Ki67 ≥ 10% after median of 6 years from the first surgery occurred in 18/49 examined tumours. Tumours with an aggressive course from outset had higher Ki67, mitotic counts, and p53. Temozolomide treatment in 156/171 patients resulted in complete response in 9.6%, partial response in 30.1%, stable disease in 28.1%, and progressive disease in 32.2% of the patients. Treatment with bevacizumab, immune checkpoint inhibitors, and peptide receptor radionuclide therapy resulted in partial regression in 1/10, 1/6, and 3/11, respectively. Median survival in APT and PC was 17.2 and 11.3 years, respectively. Tumours with Ki67 ≥ 10% and ACTH-secretion were associated with worse prognosis.

CONCLUSION

APT/PCs exhibit a wide and challenging spectrum of behaviour. Temozolomide is the first-line chemotherapy, and other oncological therapies are emerging. Treatment response continues to be difficult to predict with currently studied biomarkers.

A Pituitary Carcinoma Patient With Cerebrospinal Fluid Dissemination Showing a Good Response to Temozolomide Combined With Whole-Brain and Spinal Cord Radiotherapy: A Case Report and Literature Review

Pituitary carcinoma (PC) is extremely rare, with its incidence only accounting for 0.1%-0.2% of pituitary tumor (PT). Existing histological features, including invasiveness, cellular pleomorphism, nuclear atypia, mitosis, necrosis, etc., can be observed in pituitary adenoma (PA), invasive PA (IPA) and PC. Invasion is not the basis for the diagnosis of PC. The diagnosis of PC is often determined after the metastases are found, hence early diagnosis is extraordinarily difficult. Owing to the conventional treatment for PC may not be effective, a large portion of patients survived less than one year after diagnosis. Therefore, it is of great significance to find an efficacious treatment for PC. We report a rare case of sparsely granulated somatotroph carcinoma with cerebrospinal fluid dissemination showing a favorable treatment response to temozolomide (TMZ) combined with whole-brain and spinal cord radiotherapy.

Delayed Craniospinal Metastasis of Aggressive Nonfunctioning Pituitary Adenomas as Pituitary Carcinomas

Background Clinical behavior of pituitary neoplasms is peculiar and notoriously difficult to predict. While aggressive tumors are common, metastasis is very rare, can be highly delayed, and there are no histological or clinical features to meaningfully predict this happening. Endocrinologically silent tumors are particularly difficult, as there is less opportunity to detect early metastasis. Together, this amounts to a situation of uncertainty over the appropriate management of such tumors before and after metastasis.

Case Description The authors report two cases of nonfunctioning aggressive pituitary adenoma (APA) each requiring two transsphenoidal surgeries, a transcranial resection and radiotherapy. Both these tumors subsequently metastasized caudally along the neuraxis, years later, as a null cell carcinoma associated with a germline CHEK2 mutation and a silent Crooke's cell carcinoma. The former represents a novel oncogenetic association.

Conclusion Delayed drop dural metastasis of pituitary carcinoma is becoming increasingly recognized. Surgical resection of the distant disease to confirm the diagnosis and relieve the mass effect, followed by temozolomide chemotherapy, is the current treatment of choice. The need for both long-term follow-up in patients with APA, and a high degree of suspicion toward dural-based radiographic findings is emphasized.

Cervical Lymph Node Metastases from Central Nervous System Tumors: A Systematic Review

Introduction

Lymph node metastasis (LNM) from primary tumors of the central nervous system (CNS) is an infrequent condition, and classically it was thought that CNS tumors could not spread via the lymphatic route. Recent discoveries about this route of dissemination make its knowledge necessary for surgeons and pathologists to avoid delays in diagnosis and unnecessary treatments. The aim of this paper is to review the literature and to discuss the relevant pathogenetic mechanism and the cytologic features along with recommendations for surgical treatment of these cervical LNM.

Materials and Methods

Using PRISMA guidelines, we conducted a systematic review of the literature published from 1944 to 2021, updating the comprehensive review published in 2010 by our group.

Results

Our review includes data of 143 articles obtaining 174 patients with LNM from a primary CNS tumor. The mean age of the patients was 31.9 years (range, 0.1–87) and there were 61 females (35.1%) and 103 males (59.2%), and in 10 cases (5.7%) the gender was not specified. The more frequent sites of distant metastasis were bones (23%), lungs (11.5%) and non-cervical lymph nodes (11%).

Conclusion

Cervical LNM from CNS tumors is infrequent. Pathologic diagnosis can be obtained by fine-needle aspiration cytology in most cases, giving surgeons the option to plan the appropriate surgical treatment. Given the poor prognosis of these cases, the most conservative possible cervical dissection is usually the treatment of choice.

A Rare Case of Pituitary Carcinoma With Bone Metastases: 68Ga-DOTATATE PET/CT Findings

ABSTRACT

Pituitary carcinomas are extremely rare and aggressive tumors that comprise only 0.2% of all pituitary tumors. Because of its rarity, pituitary carcinomas are difficult to diagnose. Conventional imaging methods are inadequate to detect metastatic lesions. Pituitary carcinomas are neuroendocrine tumors and express somatostatin receptors; therefore, 68Ga-DOTATATE PET/CT may be used in the staging of these rare tumors. Herein, we present an exceptional case of pituitary carcinoma with sclerotic skeletal metastases showing 68Ga-DOTATATE uptake.

Distant Pituitary Adenoma Spread: A Systematic Review and Report of 2 Cases

BACKGROUND

Distant spread of pituitary adenoma outside the sellar/suprasellar region is classified as pituitary carcinoma. Cerebrospinal fluid (CSF)-born spread of pituitary adenoma can occur after tumor cell spillage into the CSF space after surgery, irradiation, or apoplexy and is not necessarily related to intrinsic tumor biology.

OBJECTIVE

To systematically review the literature and describe the clinical characteristics and treatment strategies of patients with pituitary carcinomas. We further present 2 cases from our institution.

METHODS

A single-center retrospective review of patients with pituitary adenoma spread to distant intracranial locations between 2000 and 2020 was performed. Electronic databases were searched from their inception to May 25, 2021, and studies describing patients with pituitary spread to distant locations were included.

RESULTS

Of 1210 pituitary adenoma cases reviewed, 2 (0.16%) showed tumor spread to distant locations. We found 134 additional cases (from 108 published articles) resulting in a total of 136 cases (61.9% were male). The time to tumor spread ranged between 0 and 516 months (median: 96 months). The follow-up duration ranged between 0 and 240 months (median: 11.5 months). All but 2 patients (98.5%) underwent surgical resection before adenoma spread. The 2 exceptions included a patient with evidence of an apoplectic event on autopsy and another patient with leptomeningeal pituitary spread but an unclear history of apoplexy. Elevated tumor markers were not linked to poor outcomes.

CONCLUSION

Distant spread of pituitary adenoma may occur after surgery, irradiation, or apoplexy. It is not necessarily associated with a malignant clinical course.

Recurrent Macroprolactinoma with Malignant Conversion to Carcinoma with Spinal Metastasis

In contrast to pituitary adenomas, pituitary carcinomas represent a rare malignant neoplasm with a remarkable high mortality. Pituitary carcinomas can arise from any pituitary tumor cell line and are determined to be carcinomas when there is distant metastasis or central nervous system dissemination. In this case vignette, we describe a rare case of malignant prolactinoma with intraspinal metastasis, and we also provide a review of relevant literature and treatment.

Tumor invasion to the spinal region after primary surgery: A case report

Background

It is believed that pituitary carcinoma is a rare disorder and arise from the transformation of benign invasive macroadenomas, and the process of this transformation takes place slowly.

Case Presentation

A 51-year-old man presented with the clinical features of Cushing syndrome and walking impairment who was diagnosed with metastatic corticotroph pituitary carcinoma to the spine region, 6 years after the initial resection of a primary invasive pituitary adenoma. He made a visit to neurosurgery and endocrinology clinic with the chief complaint of weight gain, facial and extremities swelling, paresthesia, weakness, motion and speaking impairments, and HTN which all appeared through the last 1 year; hormonal laboratory tests showed urine free cortisol (UFC) 197.8 and 367. 30 ug/24hrs (36-137), cortisol 8 am after 1 mg overnight dexamethasone test 375 ng/mL (50-250) and ACTH 59 pg/mL. MRI study revealed a mass in the brainstem with the compression effect on spinal region, pituitary imagine does not differ from the last MRI. He underwent a neurosurgery for spinal mass resection, which was successful and the total mass was resected. After surgery, the patient's condition became better.

Conclusion

Pituitary carcinoma is a rare entity impossible to recognize as a primary tumor because its diagnosis by definition requires the presence of metastasis. Clinical awareness of the rare possibility for aggressive adenomas will progress, to metastasize is essential to appropriately monitor patients for possible early detection and treatment of pituitary carcinoma.

Aggressive pituitary tumours and pituitary carcinomas

Although usually benign, anterior pituitary tumours occasionally exhibit aggressive behaviour, with invasion of surrounding tissues, rapid growth, resistance to conventional treatments and multiple recurrences. In very rare cases, they metastasize and are termed pituitary carcinomas. The time between a 'classical' pituitary tumour and a pituitary carcinoma can be years, which means that monitoring should be performed regularly in patients with clinical (invasion and/or tumour growth) or pathological (Ki67 index, mitotic count and/or p53 detection) markers suggesting aggressiveness. However, although both invasion and proliferation have prognostic value, such parameters cannot predict outcome or malignancy without metastasis. Future research should focus on the biology of both tumour cells and their microenvironment, hopefully with improved therapeutic outcomes. Currently, the initial therapeutic approach for aggressive pituitary tumours is generally to repeat surgery or radiotherapy in expert centres. Standard medical treatments usually have no effect on tumour progression but they can be maintained on a long-term basis to, at least partly, control hypersecretion. In cases where standard treatments prove ineffective, temozolomide, the sole formally recommended treatment, is effective in only one-third of patients. Personalized use of emerging therapies, including peptide receptor radionuclide therapy, angiogenesis-targeted therapy and immunotherapy, will hopefully improve the outcomes of patients with this severe condition.

Growth hormone secreting pituitary carcinomas: Case report and review of literature

OBJECTIVE

Pituitary carcinoma is a rare tumor, defined as a tumor of adenohypophyseal cells with systemic or craniospinal metastasis. We present a case of a growth hormone (GH)-secreting pituitary carcinoma with a review of literature to better characterize this disease.

DESIGN

Case report and literature review of 25 cases of GH-secreting pituitary carcinomas RESULTS: The age of diagnosis of GH-secreting carcinomas ranged 24-69 years old with a mean age of 44.4 with 52% of cases present in females. Mean latency period between diagnosis of acromegaly and transition to pituitary carcinoma was 11.4 years with mean survival being 3.4 years.

CONCLUSION

Growth hormone (GH)-secreting pituitary carcinomas are rare and hard to distinguish from aggressive pituitary adenomas. From review of literature, treatment options include debulking surgery, radiotherapy, or chemotherapy with dismal outcomes. There are no diagnostic markers or features which can predict metastatic progression of these tumors. Future studies with genomic landscapes and relevant tumor markers are needed to identify pituitary tumors most likely to metastasize.

Incidence, demographics, and survival of patients with primary pituitary tumors: a SEER database study in 2004-2016

Comprehensive investigations on the incidence and prognosis of pituitary tumors are still lacking. The present study aims to summarize the incidence, demographics, and survival outcome of pituitary adenoma on a population-based level. This study includes all pituitary adenomas reported in the Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2016 in the United States. Extensive clinical and demographic characteristics were extracted and submitted to group comparisons. The standardized incidence rate was calculated and stratified by year at diagnosis, age/sex and age/treatment groups. The Kaplan–Meier analysis and multivariable regressions were performed to identify the factors associated with overall survival. A total of 47,180 pituitary tumors were identified, including 47,030 typical adenomas, 111 uncertain behavior pituitary adenomas, and 39 pituitary carcinomas. The overall standardized incidence rate was 4.8 cases per 100,000 person-years and the annual incidence rate continually trended upwards, with a peak seen in 2015. We noticed a bimodal age-related distribution in females and a unimodal distribution in males. In the multivariate regression analysis, the factors associated with prolonged survival included typical adenoma, younger age, and smaller tumor size. Whereas, black and male patients had worse overall survival. Our study provides a reliable estimate on the incidence of pituitary adenoma and confirms that the annual standardized incidence rate is increasing. Pituitary adenomas have a satisfactory long-term prognosis and age, tumor size, and tumor subtypes are related to overall survival. Though statistically significant, our inferential findings should be constrained within the limitations of SEER database.

Pituitary Neoplasm Nomenclature Workshop: Does Adenoma Stand the Test of Time?

The WHO Classification of Endocrine Tumours designates pituitary neoplasms as adenomas. A proposed nomenclature change to pituitary neuroendocrine tumors (PitNETs) has been met with concern by some stakeholder groups. The Pituitary Society coordinated the Pituitary Neoplasm Nomenclature (PANOMEN) workshop to address the topic. Experts in pituitary developmental biology, pathology, neurosurgery, endocrinology, and oncology, including representatives nominated by the Endocrine Society, European Society of Endocrinology, European Neuroendocrine Association, Growth Hormone Research Society, and International Society of Pituitary Surgeons. Clinical epidemiology, disease phenotype, management, and prognosis of pituitary adenomas differ from that of most NETs. The vast majority of pituitary adenomas are benign and do not adversely impact life expectancy. A nomenclature change to PitNET does not address the main challenge of prognostic prediction, assigns an uncertain malignancy designation to benign pituitary adenomas, and may adversely affect patients. Due to pandemic restrictions, the workshop was conducted virtually, with audiovisual lectures and written précis on each topic provided to all participants. Feedback was collated and summarized by Content Chairs and discussed during a virtual writing meeting moderated by Session Chairs, which yielded an evidence-based draft document sent to all participants for review and approval. There is not yet a case for adopting the PitNET nomenclature. The PANOMEN Workshop recommends that the term adenoma be retained and that the topic be revisited as new evidence on pituitary neoplasm biology emerges.

Immune checkpoint inhibitor therapy for ACTH-secreting pituitary carcinoma: a new emerging treatment?

BACKGROUND

Pituitary carcinomas are rare but aggressive and require maximally coordinated multimodal therapies. For refractory tumors, unresponsive to temozolomide (TMZ), therapeutic options are limited. Immune checkpoint inhibitors (ICI) may be considered for treatment as illustrated in the present case report.

CASE

We report a patient with ACTH-secreting pituitary carcinoma, progressive after multiple lines of therapy including chemotherapy with TMZ, who demonstrated disease stabilization by a combination of ipilimumab (anti-CTLA-4) and nivolumab (anti-PD-1) ICI therapy.

DISCUSSION

Management of pituitary carcinoma beyond TMZ remains ill-defined and relies on case reports. TMZ creates, due to hypermutation, more immunogenic tumors and subsequently potential candidates for ICI therapy. This case report adds support to the possible role of ICI in the treatment of pituitary carcinoma.

CONCLUSION

ICI therapy could be a promising treatment option for pituitary carcinoma, considering the mechanisms of TMZ-induced hypermutation with increased immunogenicity, pituitary expression of CTLA-4 and PD-L1, and the frequent occurrence of hypophysitis as a side effect of ICI therapy.

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.

Clinical features and their course of pituitary carcinoma with distant metastasis in a dog

An 11-year-old male toy poodle with neurological symptoms was diagnosed with a macroscopic pituitary tumor, which produced adrenocorticotropic hormone. Radiation therapy with a linear accelerator was performed for the pituitary tumor, and resulted in good local tumor control. However, serum endogenous adrenocorticotropic hormone concentrations were uncontrollable even after the tumor disappeared. Abdominal computed tomography revealed splenic masses, and splenectomy was performed. Histopathological examination of the surgical specimen showed tumor cells with eosinophilic and finely granular cytoplasm suggestive of endocrine origin. Since these cells were positive for adrenocorticotropic hormone, the case was diagnosed as a pituitary carcinoma with distant metastasis. Necropsy revealed multiple metastases to the abdominal organs. This is the first case report describing canine pituitary carcinoma with distant metastasis.

Aggressive Pituitary Adenomas and Carcinomas

A subset of pituitary tumors present an aggressive behavior that remains difficult to predict, and in rare cases they metastasize. The current European Society for Endocrinology (ESE) guidelines for the management of aggressive pituitary tumors and carcinomas provide valuable guidance, but several issues remain unaddressed because of the scarcity of data in the literature. This article presents key clinical aspects regarding aggressive pituitary tumors and carcinomas, and also discusses some of the unanswered questions of the ESE guidelines, focusing on both diagnosis and treatment.

Definition and diagnosis of aggressive pituitary tumors

Pituitary adenomas are considered benign tumors, but approximately 10% of them can have an aggressive behavior and more rarely (0.2%) can present metastasis, being classified as pituitary carcinomas. Aggressive adenomas are generally large and invasive tumors that present unusually rapid growth and/or that grow irrespective of conventional treatment with surgery, medical therapy and radiotherapy. Nevertheless, large tumors, as well as invasive tumors are not always aggressive, with this definition being possible only after clinical follow-up of these tumors, with growth rate and response to therapies being key points to its diagnosis. The correct identification and diagnosis of aggressive adenomas is of great importance as they are associated with great morbidity and increased mortality.

Aggressive pituitary tumors in the young and elderly

Aggressive pituitary tumors (APTs) represent rare pituitary adenomas (PAs) with local invasion of surrounding tissues, increased risk for multiple recurrence, rapid tumor growth, or resistance to standard therapies. The most common APTs in children and adolescents are giant prolactinomas and somatotropinomas. Few cases of Crooke's cell adenomas, silent corticotroph adenomas and pituitary carcinomas have also been reported in the literature. Pediatric patients with APTs have higher risk of harboring germline genetic defects, most commonly in the MEN1 and AIP genes. Since certain genetic defects confer a more aggressive behavior to PAs, genetic testing should be considered in tumors with young onset and positive family history. The management of pediatric APTs involves usually a combination of standard therapies (surgical, medical, radiation). Newer agents, such as temozolomide, have been used in few cases of pediatric pituitary tumors with promising results. In the elderly, PAs are more commonly non-functioning. Their management often poses dilemmas given the coexistence of age-related comorbidities. However, standard surgical treatment and temozolomide seem to be safe and well tolerated in elderly patients.

Outcomes of Patients with Nelson's Syndrome after Primary Treatment: A Multicenter Study from 13 UK Pituitary Centers

CONTEXT

Long-term outcomes of patients with Nelson's syndrome (NS) have been poorly explored, especially in the modern era.

OBJECTIVE

To elucidate tumor control rates, effectiveness of various treatments, and markers of prognostic relevance in patients with NS.

PATIENTS, DESIGN, AND SETTING

Retrospective cohort study of 68 patients from 13 UK pituitary centers with median imaging follow-up of 13 years (range 1-45) since NS diagnosis.

RESULTS

Management of Cushing's disease (CD) prior to NS diagnosis included surgery+adrenalectomy (n = 30; eight patients had 2 and one had 3 pituitary operations), surgery+radiotherapy+adrenalectomy (n = 17; two received >1 courses of irradiation, two had ≥2 pituitary surgeries), radiotherapy+adrenalectomy (n = 2), and adrenalectomy (n = 19). Primary management of NS mainly included surgery, radiotherapy, surgery+radiotherapy, and observation; 10-year tumor progression-free survival was 62% (surgery 80%, radiotherapy 52%, surgery+radiotherapy 81%, observation 51%). Sex, age at CD or NS diagnosis, size of adenoma (micro-/macroadenoma) at CD diagnosis, presence of pituitary tumor on imaging prior adrenalectomy, and mode of NS primary management were not predictors of tumor progression. Mode of management of CD before NS diagnosis was a significant factor predicting progression, with the group treated by surgery+radiotherapy+adrenalectomy for their CD showing the highest risk (hazard ratio 4.6; 95% confidence interval, 1.6-13.5). During follow-up, 3% of patients had malignant transformation with spinal metastases and 4% died of aggressively enlarging tumor.

CONCLUSIONS

At 10 years follow-up, 38% of the patients diagnosed with NS showed progression of their corticotroph tumor. Complexity of treatments for the CD prior to NS diagnosis, possibly reflecting corticotroph adenoma aggressiveness, predicts long-term tumor prognosis.

Exploring the Role of Novel Medical Therapies for Aggressive Pituitary Tumors: A Review of the Literature-"Are We There Yet?"

Aggressive pituitary tumors account for up to 10% of pituitary tumors and are characterized by resistance to medical treatment and multiple recurrences despite standard therapies, including surgery, radiotherapy, and chemotherapy. They are associated with increased morbidity and mortality, particularly pituitary carcinomas, which have mortality rates of up to 66% at 1 year after diagnosis. Novel targeted therapies under investigation include mammalian target of rapamycin (mTOR), tyrosine kinase, and vascular endothelial growth factor (VEGF) inhibitors. More recently, immune checkpoint inhibitors have been proposed as a potential treatment option for pituitary tumors. An increased understanding of the molecular pathogenesis of aggressive pituitary tumors is required to identify potential biomarkers and therapeutic targets. This review discusses novel approaches to the management of aggressive pituitary tumors and the role of molecular profiling.

Malignant Prolactinoma With Liver Metastases Masquerading as Metastatic Gastrointestinal Stromal Tumor: A Case Report and Literature Review

Pituitary carcinomas are rare diseases defined as pituitary tumors with metastases. In this report, we describe a case of malignant prolactinoma with liver metastases masquerading as metastatic gastrointestinal stromal tumor (GIST). A 54-years-old woman received dopamine agonists for macroprolactinoma for 2 years, followed by transsphenoidal surgery due to a poor response to medical therapy. Despite the continuation of dopamine agonist after surgery, serum prolactin level progressively increased to above 8,000 ng/ml in 5 years. There was no evidence of disease recurrence on sella magnetic resonance imaging (MRI). She stopped medical therapy. Meanwhile, she was diagnosed with GIST accompanied by liver and peritoneal metastases. After a 2-months treatment with imatinib, she suddenly presented with headache and visual impairment. Sella MRI showed a 3.3-cm sized pituitary mass, and serum prolactin levels were still high. For the recurred mass, she underwent a second surgery followed by radiation therapy. During the imatinib treatment for GIST, main mass and peritoneal metastases were dramatically decreased, but liver metastases were markedly aggravated. Liver masses were eventually confirmed as metastases from prolactin-producing pituitary carcinoma and not from GIST by percutaneous biopsy. Unfortunately, she died 6 months after the second surgery due to acute renal failure and sepsis. This case suggests that highly sustained serum prolactin levels during the dopamine agonist may indicate prolactin-producing pituitary carcinomas with hidden metastases.

Lower all-cause mortality rates in patients harboring pituitary carcinoma following the introduction of temozolomide

OBJECTIVE

To evaluate the impact of temozolomide (TMZ) introduction on the survival of patients with pituitary carcinoma (PC) compared to aggressive pituitary adenoma (APA).

METHODS

Retrospective analysis of the Surveillance Epidemiology and End-Results database (SEER), including patients diagnosed with PC or APA between 1973 and 2015. Age-adjusted Kaplan-Meier analyses were performed, comparing all-cause mortality (ACM) rates before the year 2006, the time of TMZ introduction ("period 1"), and afterwards ("period 2"), in patients harboring PC and APA.

RESULTS

Among 107 patients, 18 (16.8%) harbored PC. The prevalence of PC and APA was comparable between genders, ethnicities and age strata. Patients harboring any pituitary tumor (PC or APA) had comparable risk for ACM and disease-specific mortality between the two time periods. However, among patients harboring PC, the risk for ACM was significantly lower in period 2 vs. period 1 (p = 0.021), becoming comparable to the risk of ACM in patients diagnosed with APA (p = 0.48).

CONCLUSIONS

In this large cancer-database-based analysis we observed improved overall survival in patients harboring PC in the years following the introduction of TMZ.

An Institutional Experience of Tumor Progression to Pituitary Carcinoma in a 15-Year Cohort of 1055 Consecutive Pituitary Neuroendocrine Tumors

Pituitary carcinoma is a rare disease, defined by the presence of cerebrospinal or distant metastasis of a pituitary neuroendocrine tumor (PitNET). To review our institutional experience of pituitary carcinoma, we searched the database of the UHN Endocrine Oncology Site group and the University Health Network pathology laboratory information system from 2001 to 2016. Among 1055 PitNETs from 1169 transsphenoidal resections, we identified 4 cases of pituitary carcinoma, indicating that pituitary carcinoma represents around 0.4% of PitNETs. All four patients were women. The age at initial presentation ranged from 23 to 54 years. Two patients had Cushing disease with corticotroph tumors; one was initially a densely granulated corticotroph tumor that evolved to become sparsely granulated, while the other was a Crooke cell tumor. One patient had a functioning sparsely granulated lactotroph tumor and one had a clinically silent poorly differentiated PIT1 lineage tumor. Apart from a relatively high Ki67 labeling index (≥ 10%) in three tumors, there were no cytomorphologic features at the time of initial presentation that could predict subsequent metastatic behavior. The time from diagnosis of the pituitary neuroendocrine tumor to the diagnosis of malignancy was 3 to 14 years. Therapies included somatostatin analogs, external beam radiotherapy, chemotherapies including capecitabine/temozolomide, everolimus, sunitinib, bevacizumab, and peptide receptor radionuclide therapy (PRRT). One patient died of disease 18 years after initial diagnosis, underscoring the protracted course of this ultimately fatal neuroendocrine malignancy.

A Population-Level Analysis of Pituitary Carcinoma from the National Cancer Database

Objectives  Pituitary carcinoma is a rare entity with fewer than 200 total cases reported in the English literature. Analysis of the population-level data from the National Cancer Database (NCDB) affords the opportunity to study this poorly understood tumor type. Methods  The NCDB was queried for site, histology, and metastasis codes corresponding to pituitary carcinoma. Statistical analyses were performed to determine factors associated with overall survival (OS). Results  A total of 92 patients with pituitary carcinoma met inclusion criteria. The 1 and 5 years of OS for all patients was 93.3% (95% confidence interval [CI]: 88.2-98.6%) and 80.0% (95% CI: 71.6-89.4%), respectively. Patients with invasive primary tumor behavior had 1 and 5 years of OS of 69.2% (95% CI: 48.2-99.5%) and 52.7% (95% CI: 31.2-89.2%), respectively. Multivariate analysis demonstrated that compared with benign primary behavior, invasive behavior had increased all-cause mortality (hazard ratio [HR], 1,296, 95% CI: 15.1- > 2,000). Surgery without adjuvant radiation or chemotherapy was the most common therapy (48.9%), followed by no treatment (40.2%). Compared with surgery alone, no treatment had worse OS (HR, 11.83, 95% CI: 1.41-99.56). Increasing age and female sex were both associated with increased mortality. Conclusions  The most common treatment for pituitary carcinoma is surgery alone followed by no surgery. Surgery alone has significantly better OS compared with no treatment. The efficacy of radiation, chemotherapy, and neurohormonal treatments needs to be examined with prospective studies.

Aggressive and Malignant Prolactinomas

Prolactin-secreting tumors (prolactinomas) represent the most common pituitary tumor type, accounting for 47-66% of functional pituitary tumors. Prolactinomas are usually benign and controllable tumors as they express abundant levels of dopamine type 2 receptor (D2), and can be treated with dopaminergic drugs, effectively reducing prolactin levels and tumor volume. However, a proportion of prolactinomas exhibit aggressive features (including invasiveness, relevant growth despite adequate dopamine agonist treatment, and recurrence potential) and few may exhibit metastasizing potential (carcinomas). In this context, the clinical, pathological, and molecular definitions of malignant and aggressive prolactinomas remain to be clearly defined, as primary prolactin-secreting carcinomas are similar to aggressive adenomas until the presence of metastases is detected. Indeed, standard molecular and histological analyses do not reflect differences between carcinomas and adenomas at a first glance and have limitations in prediction of the aggressive progression of prolactinomas, wherein the causes underlying the aggressive behavior remain unknown. Herein we present a comprehensive, multidisciplinary review of the most relevant epidemiological, clinical, pathological, genetic, biochemical, and molecular aspects of aggressive and malignant prolactinomas.

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.

Recent advances in understanding corticotroph pituitary tumor initiation and progression

Cushing’s disease is the most frequent form of hypercortisolism and is caused by hypophyseal corticotroph adenomas secreting excessive amounts of adrenocorticotropic hormone. Most of the tumors develop sporadically and only a limited number of corticotroph adenomas have been found to be associated with different neuroendocrine syndromes or with familial isolated pituitary adenomas. The pathogenic mechanisms of corticotroph adenomas are largely unknown, but the discovered aberrant chaperoning activity of heat shock protein 90 on the one hand and the presence of ubiquitin-specific protease 8 mutations on the other hand partially explained the causes of their development. Corticotroph tumors arise initially as benign microadenomas but with time form invasively growing aggressive macroadenomas which can switch to corticotroph carcinomas in extremely rare cases. The mechanisms through which corticotroph tumors escape from glucocorticoid negative feedback are still poorly understood, as are the processes that trigger the progression of benign corticotroph adenomas toward aggressive and malignant phenotypes. This review summarizes recent findings regarding initiation and progression of corticotroph pituitary tumors.