Ependymal Pituicytoma

**Semantic type:** Neoplastic Process

**Definition:** A very rare, low-grade neoplasm that arises from the posterior pituitary. It is composed of epithelioid and oncocytic cells forming sheets and fascicles. It shows histopathological features reminiscent of ependymomas, including perivascular pseudorosettes and true rosettes. There is no evidence of necrosis or increased mitotic activity. Despite the presence of ependymal histopathological features, these neoplasms probably are not related to ependymomas. Their prognosis is unknown.

**Synonyms:** - Sellar Ependymoma