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

Abstract

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 TTF-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.

Pathology of sellar tumors: A contemporary diagnostic approach

“…Modern understanding of posterior pituitary tumors is that they represent a spectrum of low-grade tumor types with a single common characteristic: thyroid transcription factor 1 (TTF1) positivity (30,31). Spindle-cell oncocytoma, pituicytoma and granular cell tumor of the sellar region originate from pituicytes of the posterior pituitary or infundibulum.…”