title: Pituitary carcinoma in situ.
abstract: OBJECTIVE
  Pituitary carcinomas are extremely rare tumors associated with poor prognosis despite surgery, radiation, and chemotherapy. The hallmark of diagnosis implies subarachnoid, brain, or systemic tumor spread.
  
  
  METHODS
  We report a case of rapid transformation of atypical nonfunctioning pituitary adenoma to a carcinoma.
  
  
  RESULTS
  A 64-year-old woman presented with sudden onset of ophthalmoplegia. Magnetic resonance imaging (MRI) scan showed a pituitary macroadenoma (2.2 x 2.1 cm) with invasion of the right cavernous sinus. Biochemical data was consistent with a nonfunctioning pituitary adenoma. Pathology showed a pituitary adenoma with negative immunohistochemistry for pituitary hormones. The patient returned a month later with weakness, lethargy, and a dilated nonreactive right pupil. MRI showed an invasive large mass (5 x 4.7 cm). After an emergent second transsphenoidal surgery, histopathologic examination revealed a widely infiltrative neoplasm invading the overlying mucosa and showing a high mitotic activity and necrosis and a very high Ki-67 (MIB-1) proliferation index (80%). MIB-1 retrospectively performed on the first specimen was also elevated (30%). Soon after the second surgery, MRI showed a 7.9 x 8.0 cm mass that metastasized to dura mater and extended into the right orbit, right middle cranial fossa, nasopharynx, clivus, posterior fossa, and along the right tentorium cerebelli, resulting in significant compression of the brainstem.
  
  
  CONCLUSIONS
  Development of a pituitary carcinoma from an adenoma is an exceptional occurrence and predictors of such course are currently lacking. A very high Ki-67 proliferation index should raise concern of a pituitary carcinoma in situ or premetastatic carcinoma.
authors: Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
authors: Francisco J
authors: FJ
authors: Pasquel
authors: Cristina
authors: C
authors: Vincentelli
authors: Daniel J
authors: DJ
authors: Brat
authors: Nelson M
authors: NM
authors: Oyesiku
authors: Adriana G
authors: AG
authors: Ioachimescu
mesh_terms: D002277:Carcinoma / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000175:diagnosis*