Adenohypophyseal hyperfunction syndromes and posterior pituitary tumors: prevalence, clinical characteristics, and pathophysiological mechanisms

Oncocytic pituicytoma in a patient with Cushing's disease: a case report and narrative literature review

Background

Posterior pituitary tumors (PPTs) are extremely rare, with fewer than 400 cases reported to date. In 2022, the World Health Organization (WHO) classified four types of tumors originating from the posterior pituitary: traditional pituicytoma, oncocytic pituicytoma, granular pituicytoma, and ependymal pituicytoma. To our knowledge, only one subject with coexistence of Cushing's disease and oncocytic pituicytoma (spindle cell oncocytoma) has been reported, but the clinical features of this patient were not described in detail.

Case presentation

We presented a case of a patient with Cushing's syndrome and a pituitary mass. Transsphenoidal surgery was performed, and pathologic examination revealed two distinct tumors: a corticotroph adenoma with a diameter of less than 2 mm and a larger oncocytic pituicytoma. Post-surgery serum cortisol was 51 nmol/L, indicating complete remission. Corticotroph adenoma or corticotroph hyperplasia was identified after surgery in less than half of the subjects with Cushing's disease and PPT.

Conclusions

Our study indicates that Cushing's disease in patients with PPT may be caused by the existence of collision lesions, with corticotroph adenoma or hyperplasia being difficult to detect due to their small dimensions.

Posterior pituitary tumors and other rare entities involving the pituitary gland

Non-neuroendocrine tumors account for around 10% of all primary neoplasms of the sella. If meningiomas, craniopharyngiomas, and germ cell tumors are excluded, the remaining lesions include a broad spectrum of uncommon, benign, and aggressive, often diagnostically challenging lesions. This review aims to summarize the essential clinicopathological features of tumors of the posterior pituitary gland, infundibulum spectrum expressing thyroid transcription factor 1, and primary sellar atypical rhabdoid teratoid tumor, and provide the criteria for their diagnosis and management.

Treatment modalities and outcomes of granular cell tumors and spindle cell oncocytomas of the pituitary gland: an analysis of two national cancer databases

BACKGROUND

Spindle cell oncocytomas (SCO) and granular cell tumors (GCT) are rare primary pituitary neoplasms; the optimal treatment paradigms for these lesions are unknown and largely unexplored. Thus, using national registries, we analyze the epidemiology, management patterns, and surgical outcomes of SCOs and GCTs.

METHODS

The National Cancer Database (NCDB; years 2003-2017) and the Surveillance, Epidemiology, and End Results Program (SEER; years 2004-2018) were queried for patients with pituitary SCOs or GCTs. Incidence, extent of surgical resection, and rate of postoperative radiation use for subtotally resected lesions comprised the primary outcomes of interest. All-cause mortality was also analyzed via time-to-event Kaplan-Meier curves.

RESULTS

SCOs and GCTs have an annual incidence of 0.017 and 0.023 per 1,000,000, respectively. They comprise 0.1% of the benign pituitary tumors registered in NCDB. A total of 112,241 benign pituitary tumors were identified in NCDB during the study period, of which 83 (0.07%) were SCOs and 59 (0.05%) were GCTs. Median age at diagnosis was 55 years, 44% were females, and median maximal tumor diameter at presentation was 2.1 cm. Gross total resection was achieved in 54% patients. Ten patients (7%) had postoperative radiation. Comparing patients with GCTs versus SCOs, the former were more likely to be younger at diagnosis (48.0 vs. 59.0, respectively; p < 0.01) and female (59% vs. 34%, p = 0.01). GCTs and SCOs did not differ in terms of size at diagnoses (median maximal diameter: 1.9 cm vs. 2.2 cm, respectively; p = 0.59) or gross total resection rates (62% vs. 49%, p = 0.32). After matching SCOs and GCTs with pituitary adenomas on age, sex, and tumor size, the former were less likely to undergo gross total resection (53% vs. 72%; p = 0.03). Patients with SCOs and GCTs had a shorter overall survival when compared to patients with pituitary adenomas (p < 0.01) and a higher rate of thirty-day mortality (3.1% vs 0.0%; p = 0.013).

CONCLUSION

SCOs and GCTs are rare pituitary tumors, and their management entails particular challenges. Gross total resection is often not possible, and adjuvant radiation might be employed following subtotal resection.

Granular cell tumor of the neurohypophysis presenting as a third ventricle mass

Granular cell tumors of the neurohypophysis (GCT) are rare benign neoplasms belonging, along with pituicytoma and spindle cell oncocytoma, to the family of TTF1-positive low-grade neoplasms of the posterior pituitary gland. GCT usually present as a solid sellar mass, slowly growing and causing compressive symptoms over time, occasionally with suprasellar extension. They comprise polygonal monomorphous cells with abundant granular cytoplasm, which is ultrastructurally filled with lysosomes. Here we report the case of a GCT presenting as a third ventricle mass, radiologically mimicking chordoid glioma, with aberrant expression of GFAP and Annexin-A, which lends itself as an example of an integrated diagnostic approach to sellar/suprasellar and third ventricle masses.

Pituicytoma Associated with Suspected Cushing’s Disease: Two Case Reports and a Literature Review

(1) Background: Pituicytomas are rare gliomas located in the neurohypophysis or infundibulum. A misdiagnosis of pituicytoma as pituitary adenoma is common because of similar location and occasional endocrine disturbances. (2) Case presentation: We present two cases with the comorbidity of pituicytoma and Cushing’s disease (CD). Case 1 is that of a 51-year-old woman, the first reported case of the comorbidity of pituicytoma, CD, and central diabetes insipidus. She received a diagnosis of CD and central diabetes insipidus. After transsphenoidal surgery, histopathology confirmed the diagnosis of pituicytoma and adrenocorticotropin-secreting microadenoma; case 2 is that of a 29-year-old man who received a biochemical diagnosis of CD, but he received a histopathological confirmation of only pituicytoma. Both patients achieved a remission of hypercortisolism without relapse during the follow-up, but they developed hypopituitarism after surgery. We also reviewed all published 18 cases with the comorbidity of pituicytoma and any pituitary adenoma. (3) Conclusions: Pituicytoma might present pituitary hyperfunction disorders such as CD or acromegaly, with or without pathologically confirmed pituitary adenoma. CD is the most common hyperpituitarism occurring concurrently with pituicytomas. The remission rate and hypopituitarism after surgery seem similar or slightly lower in CD than in common pituitary adenomas, but the long-term prognosis is unexplored.

Recommendation to improve the WHO classification of posterior pituitary tumors as a unique entity: evidence from a large case series

INTRODUCTION

Most studies reporting posterior pituitary tumors (PPTs) are small case series or single cases.

METHODS

Patients with a histological diagnosis of PPT from January 2010 to December 2021 in a tertiary center were identified. We reported clinical symptoms, endocrine assessments, radiological and pathological features, and surgical outcomes of PPTs.

RESULTS

A total of 51 patients (23 males, 51.3 ± 10.3 years old) with PPT were included in this study. Major symptoms were visual defects, headache, and hypopituitarism, while diabetes insipidus was uncommon (9.8%). The typical radiological feature was homogeneous enhancement (84.3%) of a regular-shaped mass on T1 contrast imaging without cystic change, calcification, or cavernous sinus invasion. We achieved gross total resection in 38/51 patients (74.5%). Pathologically, all tumors showed thyroid transcription factor 1 immunoreactivity. Among 29 patients with suprasellar PPTs, postoperative hemorrhage due to tumor residue was encountered in 2/15 cases in the transcranial group and 0/14 in the endoscopy group. Patients with spindle cell oncocytoma (SCO) were more likely to be surgically treated (25% vs 0%, P = 0.018), harbor a higher Ki-67 index (16.7% vs 0% > 5% P = 0.050), and present a lower 2-year recurrence-free survival rate (67.5% vs 90.9%) compared with patients with pituicytoma or granular cell tumor.

CONCLUSION

PPTs should be considered in the differential diagnosis of patients with sellar and suprasellar masses with a regular lesion with homogeneous enhancement. SCOs had high proliferation activity and risk of recurrence.

A human ACTH-secreting corticotroph tumoroid model: Novel Human ACTH-Secreting Tumor Cell in vitro Model

BACKGROUND

Cushing disease (CD), although rare, is a life-threatening disorder caused by an adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma, which leads to excess adrenal-derived cortisol. Efficacious and safe medical therapies that control both hormonal hypersecretion and pituitary corticotroph tumor growth remain an unmet need in the management of CD. Translational research in pituitary tumors has been significantly hampered by limited quantities of surgically resected tissue for ex vivo studies, and unavailability of human pituitary tumor cell models.

METHODS

To characterize human corticotroph tumors at the cellular level, we employed single cell RNA-sequencing (scRNA-seq) to study 4 surgically resected tumors. We also used microarrays to compare individualized paired consecutive culture passages to understand transcriptional shifts as in vitro cultures lost ACTH secretion. Based on these findings, we then modified our in vitro culture methods to develop sustained ACTH-secreting human corticotroph tumoroid cultures.

FINDINGS

scRNA-seq identified 4 major cell populations, namely corticotroph tumor (73.6%), stromal (11.2%), progenitor (8.3%), and immune cells (6.8%). Microarray analysis revealed striking changes in extracellular matrix, cell adhesion and motility-related genes concordant with loss of ACTH secretion during conventional 2D culture. Based on these findings, we subsequently defined a series of crucial culture nutrients and scaffold modifications that provided a more favorable trophic and structural environment that could maintain ACTH secretion in in vitro human corticotroph tumor cultures for up to 4 months.

INTERPRETATION

Our human corticotroph tumoroid model is a significant advance in the field of pituitary tumors and will further enable translational research studies to identify critically needed therapies for CD.

FUNDING

This work was partly funded by NCI P50-CA211015 and the Warley Trust Foundation.