Pituicytoma: Review of commonalities and distinguishing features among TTF-1 positive tumors of the central nervous system

- A concise review of the clinical and pathological features of pituicytoma.
- A discussion on how to differentiate this entity from other more common pituitary neoplasms in daily practice.
- A special highlight on recent research suggesting a common origin of TTF1 positive neoplasms in the CNS.

Pituicytoma is a rare low-grade glial neoplasm that originates in the distribution of the neurohypophysis, including the posterior pituitary lobe and infundibular stalk. The tumor cells resemble pituicytes, which are specialized glial cells of the neurohypophysis. Pituicytoma can be misdiagnosed pre-operatively as a pituitary adenoma due to overlapping clinical and neuroimaging features between these two entities. Pituicytoma can also mimic other neoplasms of the sellar and parasellar regions microscopically - meningioma, schwannoma and pilocytic astrocytoma - and shares immunohistochemical expression of TTF-1 with spindle cell oncocytoma and granular cell tumor of the sellar region, suggesting a common histogenesis. In this short review, we present the key features of pituicytoma, discuss commonalities and distinguishing features from other neoplasms of the sellar and parasellar regions and highlight the importance of recognizing this tumor entity for clinical and surgical management.