Posterior pituitary tumours: patient outcomes and determinants of disease recurrence or persistence

Abstract

Objective: Posterior pituitary tumours (PPTs) are rare neoplasms with the four recognised subtypes unified by thyroid transcription factor -1 (TTF-1) expr ession, according to the 2017 WHO classification. Though traditionally defined as low-grad e neoplasms, a substantial proportion of them show recurrence/persistence fo llowing surgery. Methods: We selected patients with PPTs in our cohort of 1760 patients operated for pituitary tumours over the past 10 years (2010–2019). The c linical, radiological, hormonal, histopathological profiles and long-term outcomes of t he three cases identified (two pituicytomas and one spindle cell oncocytoma, SC O) were analysed. Following a literature review, data of all published cases with documented TTF-1 positive pituicytomas and SCOs were analysed to determine the predictors of recurrence/ persistence in these tumours. Results: Patients presented with compressive features or hypogonadism. T wo had sellar-suprasellar masses. One had a purely suprasellar mass with a pr e-operative radiological suspicion of pituicytoma. Two were operated by transsphenoidal surgery and one transcranially guided by neuronavigation. Histopathology confirmed spindle cells in a storiform arrangement and low Ki67 index. Immunohistochemistry showed positive TTF-1, S-100 expression and variable positivity for EMA, viment in and GFAP. Re-evaluation showed recurrence/persistence in two patients. A literature review of recurrent/persistent pituicytoma (n = 17) and SCO (n = 9) cases revealed clinical clues (headache for pituicytomas, male gender for SCO), baseline tumour size (≥20.5 mm with sensitivity exceeding 80%) and longer follow-up duration a s determinants of recurrence/persistence. Conclusion: PPTs are rare sellar masses with quintessential TTF-1 positivit y. Recurrent/ persistent disease following surgery is determined by greater tumour size at baseline and duration of follow-up. This warrants intensive and long-term su rveillance in these patients.

Keywords

• pituicytomas
• posterior pituitary tumours
• spindle cell oncocytomas
• ttf-1