title: Prolactin-cell adenoma with signet-ring cells: a case report.
abstract: OBJECTIVE
  Signet-ring cell changes in the pituitary adenomas are extremely rare. To date, there have been only two reports documenting signet-ring cells in pituitary adenomas, one in a growth-hormone cell adenoma and the other in a nullcell adenoma. This report describes, for the first time, signet-ring cells in a prolactincell adenoma.
  
  
  METHODS
  The patient is a 46-year-old male who presented with severe headache and acute on chronic visual loss. Radiographic studies demonstrated a large cystic pituitary lesion with evidence of pituitary apoplexy. Laboratory values were consistent with a prolactin-cell adenoma. The patient underwent transsphenoidal resection of the prolactin-cell adenoma with significant post-operative improvement.
  
  
  RESULTS
  The tumor was composed of sheets of monomorphic round cells with conspicuous nuclei and granular cytoplasm, consistent with pituitary adenoma. Many cells had eccentric, often crescentic-shaped nuclei, imparting a signet-ring appearance and immunostaining was positive for prolactin, denoting an atypical prolactin-cell adenoma. The MIB-1 labeling index was slightly elevated. Electron microscopy demonstrated the presence of vacuolated areas in the cytoplasm that were not membrane bound and did not have specific inclusions.
  
  
  CONCLUSIONS
  This case augments the literature on pituitary adenomas with signet-ring cells. The clinical significance of signet-ring cells in pituitary adenomas is unknown. Accumulation of clinical cases, together with the advances in molecular techniques and experimental models, may yield further insight.
authors: Department of Neurosurgery, Mount Sinai Medical Center, New York, NY, USA. emanuela.binello@mssm.edu
authors: E
authors: E
authors: Binello
authors: C
authors: C
authors: Cunliffe
authors: K D
authors: KD
authors: Post
authors: G M
authors: GM
authors: Kleinman
mesh_terms: D000236:Adenoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D018279:Carcinoma, Signet Ring Cell / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D011388:Prolactin / Q000378:metabolism*; D016896:Treatment Outcome
chemical_list: D011388:Prolactin