title: Unusual double pituitary adenoma: a case report.
abstract: We report the case of a 60-year-old woman with Cushing disease. Magnetic resonance imaging (MRI) revealed a large sellar and suprasellar mass involving the right cavernous sinus, consistent with pituitary macroadenoma. It was resected by transsphenoidal surgery. Light microscopy revealed two separate pituitary adenomas with different histologic and immunohistochemical features. One was amphophilic and strongly Periodic Acid-Schiff (PAS) positive, the other chromophobic and PAS negative. The former tumor was immunopositive for adrenocorticotropic hormone (ACTH); approximately 30% tumor cells were immunopositive for MGMT (O6-Methylguanine-DNA Methyl-Transferase). The second tumor was a PAS negative, luteinizing hormone (LH) and alpha subunit immunopositive gonadotroph adenoma. In this tumor, about 90% of the cells were immunopositive for MGMT. The Ki-67 nuclear indices of the two tumors were 6% and 2%. Our case represents a rare combination of two morphologically different pituitary adenomas, one producing ACTH and the other LH and alpha subunit. The two tumors differed not only in Ki-67 labeling indices but in MGMT immunoexpression as well.
authors.affiliation: Department of Laboratory Medicine, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada. rotondof@smh.ca
authors.forename: Fabio
authors.initials: F
authors.lastname: Rotondo
authors.forename: Nasima
authors.initials: N
authors.lastname: Khatun
authors.forename: Bernd W
authors.initials: BW
authors.lastname: Scheithauer
authors.forename: Eva
authors.initials: E
authors.lastname: Horvath
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Marotta
authors.forename: Michael
authors.initials: M
authors.lastname: Cusimano
authors.forename: Kalman
authors.initials: K
authors.lastname: Kovacs
mesh_terms: D000236:Adenoma / Q000378:metabolism / Q000473:pathology*; D015254:DNA Modification Methylases / Q000378:metabolism; D045643:DNA Repair Enzymes / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000378:metabolism / Q000473:pathology*; D047748:Pituitary ACTH Hypersecretion / Q000378:metabolism / Q000473:pathology; D010911:Pituitary Neoplasms / Q000378:metabolism / Q000473:pathology*; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D025521:Tumor Suppressor Proteins; D015254:DNA Modification Methylases; C515491:MGMT protein, human; D045643:DNA Repair Enzymes