Primary Tumors of the Posterior Pituitary Gland: A Systematic Review of the Literature in Light of the New 2017 World Health Organization Classification of Pituitary Tumors

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.

Epidemiology of common and uncommon adult pituitary tumors in the U.S. according to the 2017 World Health Organization classification

PURPOSE

To examine the contemporary epidemiology of adult pituitary tumors with a particular focus on uncommon tumor types, using the 2017 WHO Classification of pituitary tumors.

METHODS

Adult patients presenting with a pituitary or sellar tumor between 2004 and 2017 were identified from the U.S. National Cancer Database, with tumor type categorized according to the 2017 WHO classification. Descriptive epidemiological statistics were evaluated and reported for all pituitary tumor types and subtypes.

RESULTS

113,349 adults with pituitary tumors were identified, 53.0% of whom were female. The majority of pituitary tumors were pituitary adenomas (94.0%), followed by craniopharyngiomas (3.8%). Among pituitary adenomas, whereas 71.6% of microadenomas presented in females, only 46.7% of macroadenomas and 41.3% of giant adenomas did (p < 0.001). For craniopharyngiomas, 71.2% were adamantinomatous and 28.8% were papillary, with adamantinomatous tumors associated with Black non-Hispanic race/ethnicity (OR_adj = 2.44 vs. White non-Hispanic, 99.9 %CI = 1.25-4.75, p < 0.001) in multivariable analysis. The remaining 0.7% (n = 676) of pathology-confirmed pituitary tumor types were composed of: 21% tumors of the posterior pituitary, 16% chordomas, 11% pituitary carcinomas (i.e. adenohypophyseal histology with metastasis; herein most frequently to bone), 10% meningiomas, 8% germ cell tumors, 7% hematolymphoid (largely DLBCLs), and 4% neuronal/paraneuronal (largely gangliogliomas). Pituitary carcinomas and posterior pituitary tumors demonstrated a male predilection (62.2% and 56.0%, respectively), whereas sellar meningiomas predominated in females (84.1%). Age, race/ethnicity, tumor size, and overall survival further varied across uncommon pituitary tumor types.

CONCLUSIONS

Our findings provide a detailed contemporary dissection of the epidemiology of common and uncommon adult pituitary tumors in the context of WHO2017.

Comprehensive Genomic Characterization of A Case of Granular Cell Tumor of the Posterior Pituitary Gland: A Case Report

Granular cell tumors of the pituitary belong to a rare family of neoplasms, arising from the posterior pituitary gland. Although considered benign, they may cause significant morbidity and residual disease after resection can lead to poor clinical outcomes. Currently, there is no known medical therapy for any posterior pituitary gland tumor, in part due to sparse molecular characterization of these lesions. We report data from whole exome sequencing of a case of granular cell tumor of the pituitary, performed under an institutional review board approved protocol. A 77 year-old female underwent resection of an incidentally diagnosed pituitary mass that was causing radiographic compression of the optic nerves with a subclinical temporal field defect and central hypothyroidism. The pathology of the resected specimen demonstrated a granular cell tumor of the posterior pituitary gland. Whole-exome sequencing revealed mutations predicted to be deleterious in key oncogenes, SETD2 and PAX8, both of which have been described in other cancers and could potentially be amenable to targeted therapies with existing approved drugs, including immune checkpoint inhibitors and histone deacetylase inhibitors, respectively. To our knowledge, this is the first comprehensive genomic characterization of granular cell tumor of the posterior pituitary gland. We report mutations in oncogenes predicted to be deleterious and reported in other cancers with potential for therapeutic targeting with existing pharmacologic agents. These data provide new insights into the molecular pathogenesis of GCT of the pituitary and may warrant further investigation.

Case Report: Sellar Ependymomas: A Clinic-Pathological Study and Literature Review

Ependymomas are primary glial tumors arising from cells related to the ependymal lining of the ventricular system. They are classified into at least nine different molecular subtypes according to molecular phenotype, histological morphology, and tumor location. Primary sellar ependymoma is an extremely rare malignancy of the central nervous system, with only 12 known cases reported in humans. We herein report a case of ependymoma located at the pituitary region in a 44-year-old female patient and discuss the molecular subtype, natural history, clinical presentation, radiological findings, histological features, immunohistochemical characteristics, ultrastructural examinations, treatment, and prognosis of sellar ependymoma. This case report may serve as a helpful reference for clinicians and radiologists in clinical practice.