title: Null cell adenoma of the pituitary with features of plurihormonality and plurimorphous differentiation.
abstract: The case of a 35-year-old man with pituitary macroadenoma who was complaining of reduced sexual activity is presented. Histologic examination showed a chromophobic adenoma corresponding mainly to a null cell adenoma at the ultrastructural level. Focal plurihormonality and plurimorphous differentiation of adenoma cells were demonstrated by immunohistochemical and electron-microscopic studies. It is suggested that adenomatous null cells represent pluripotent progenitor cells capable of transforming to different hormone-producing cell types. The factors accounting for differentiating to various cell populations have yet to be elucidated.
authors.affiliation: Department of Pathology, St Michael's Hospital, Canada.
authors.forename: G
authors.initials: G
authors.lastname: Kontogeorgos
authors.forename: E
authors.initials: E
authors.lastname: Horvath
authors.forename: K
authors.initials: K
authors.lastname: Kovacs
authors.forename: D W
authors.initials: DW
authors.lastname: Killinger
authors.forename: H S
authors.initials: HS
authors.lastname: Smyth
mesh_terms: D000236:Adenoma / Q000175:diagnosis* / Q000648:ultrastructure; D000328:Adult; D002454:Cell Differentiation; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D010907:Pituitary Hormones / Q000097:blood*; D010911:Pituitary Neoplasms / Q000175:diagnosis* / Q000648:ultrastructure
chemical_list: D010907:Pituitary Hormones