title: Epithelioid pituicytoma.
abstract: BACKGROUND
  Pituicytomas are rare tumors of the sellar region that are derived from specialized glial cells called pituicytes. They characteristically exhibit spindle-cell features and fascicular or storiform patterns of growth. No other histological variants of this tumor have been described.
  
  
  METHODS
  Here we report a diagnostically challenging case of pituicytoma in a 42-year-old man with a sellar mass arising from the pituitary stalk. On histological examination, the tumor displayed an epithelioid histoarchitecture with no characteristic spindle-cell or fascicular growth features. Strong immunopositivity for the pituicyte marker thyroid transcription factor-1 within tumor cells proved essential for diagnosing this unusual pituicytoma variant.
  
  
  CONCLUSIONS
  Pituicytomas may display epithelioid rather than fascicular or storiform histoarchitecture. Epithelioid pituicytoma variants may be diagnosed in cases such as ours in which both the clinical findings and immunohistochemical analysis suggest a tumor derived from pituicytes.
authors: Department of Neurological Surgery, Columbia University Medical Center, New York, New York, USA. jae2109@columbia.edu
authors: Jason A
authors: JA
authors: Ellis
authors: Nadejda M
authors: NM
authors: Tsankova
authors: Randy
authors: R
authors: D'Amico
authors: John C
authors: JC
authors: Ausiello
authors: Peter
authors: P
authors: Canoll
authors: Marc K
authors: MK
authors: Rosenblum
authors: Jeffrey N
authors: JN
authors: Bruce
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D003399:Craniotomy; D003937:Diagnosis, Differential; D015622:Epithelioid Cells / Q000473:pathology*; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010902:Pituitary Gland / Q000473:pathology; D010911:Pituitary Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery*
chemical_list: D014408:Biomarkers, Tumor