title: Incidence, hormonal distribution and postoperative follow up of atypical pituitary adenomas.
abstract: OBJECTIVE
  To assess the incidence, hormonal activity and postoperative follow up of the cases that are histopathologically diagnosed as atypical pituitary adenoma (APA) in our series.
  
  
  METHODS
  In this study, 13 atypical pituitary adenoma cases, by the WHO 2004 criteria, among the 146 pituitary adenoma patients operated on in our clinic between January 2009 and May 2012 by endoscopic endonasal transsphenoidal approach were included.
  
  
  RESULTS
  In histological studies, 133 cases were diagnosed as typical pituitary adenoma (91.1%) and 13 cases were APAs (8.9%) of which 10 were male (76.9%) and 3 were female (23.1%), ranged between 27 and 80 (mean 52.7) ages. Histopathological distribution of APAs was 9 nonsecretory adenomas (69.3%), 3 prolactinomas (23.1%) and 1 somatostatinoma (7.6%). Asymptomatic pituitary apoplexy was diagnosed in 4 cases (30.7%). Eleven cases of typical pituitary adenomas (8.2%) and 5 cases of the atypical pituitary adenomas (38.4%) were re-operated due to tumor recurrences.
  
  
  CONCLUSIONS
  Accurate histopathological examination shows that atypical pituitary adenoma is not a rare disease. Although it is not the only determinant, APAs are more prone to recurrence than typical adenomas. In our opinion, if total resection is not possible for the patients with APA, close postoperative follow up and additional curative therapy modalities are needed.
authors.affiliation: Ankara Numune Research and Education Hospital, Department of Neurosurgery, Ankara, Turkey. alierdemyildirim@gmail.com
authors.forename: Ali Erdem
authors.initials: AE
authors.lastname: Yildirim
authors.forename: Denizhan
authors.initials: D
authors.lastname: Divanlioglu
authors.forename: Osman Arikan
authors.initials: OA
authors.lastname: Nacar
authors.forename: Engin
authors.initials: E
authors.lastname: Dursun
authors.forename: Mert
authors.initials: M
authors.lastname: Sahinoglu
authors.forename: Tuba
authors.initials: T
authors.lastname: Unal
authors.forename: Ahmed Deniz
authors.initials: AD
authors.lastname: Belen
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000378:metabolism / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D010907:Pituitary Hormones / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000453:epidemiology / Q000378:metabolism / Q000601:surgery*; D011184:Postoperative Period; D013100:Sphenoid Bone / Q000601:surgery; D016896:Treatment Outcome
chemical_list: D010907:Pituitary Hormones