title: Typical and atypical pituitary adenomas: a single-center analysis of outcome and prognosis.
abstract: OBJECTIVE
  In 2004, the World Health Organization defined atypical pituitary adenomas as those with a Ki-67 expression > 3%, an excessive p53 expression and increased mitotic activity. As the usefulness of this classification is controversial, we reviewed typical and atypical pituitary adenomas to compare the clinical and prognostic features.
  
  
  METHODS
  We retrospectively reviewed 343 consecutive pituitary adenomas. Atypical pituitary adenomas represented 18.7% of cases. All patients were operated on at the Department of Neurosurgery of our institution and were followed up at the Hypothalamic-Pituitary Disease Unit of the same institution. The median follow-up time was 75 months (range 7-345).
  
  
  RESULTS
  Younger age at diagnosis as well as immunohistochemical positivity for adrenocorticotropic hormone and prolactin correlated with a higher risk of atypical pituitary adenomas, whereas typical and atypical pituitary adenomas did not differ with regard to gender, tumor size, recurrence risk and disease-free survival time (DFST). Among the 219 patients who underwent radical surgery, a Ki-67 expression ≥ 1.5% was associated with a higher risk of recurrence and a worse DFST, even after correction for age at diagnosis, gender, immunohistochemical classification, tumor size, invasiveness and Knosp classification [p = 0.01; hazard ratio (HR) 2.572; 95% confidence interval (CI) 1.251-5.285). Pituitary adenomas with a Ki-67 expression ≥ 1.5% showed a worse DFST as compared to pituitary adenomas with a Ki-67 expression < 1.5% (HR 2.166; 95% CI 1.154-4.064).
  
  
  CONCLUSIONS
  In this series, atypical and typical pituitary adenomas did not differ with regard to recurrence and DFST. Pituitary adenomas with a Ki-67 expression ≥ 1.5% showed a higher recurrence risk and a worse DFST as compared to those with a Ki-67 expression < 1.5%. We suggest that a Ki-67 expression ≥ 1.5% may be useful as a prognostic marker, though this will need to be confirmed by prospective, multicenter data.
authors: Section of Endocrinology, Department of Internal Medicine, Catholic University, School of Medicine, Rome, Italy.
authors: Sabrina
authors: S
authors: Chiloiro
authors: Francesco
authors: F
authors: Doglietto
authors: Barbara
authors: B
authors: Trapasso
authors: Donato
authors: D
authors: Iacovazzo
authors: Antonella
authors: A
authors: Giampietro
authors: Francesco
authors: F
authors: Di Nardo
authors: Chiara
authors: C
authors: de Waure
authors: Libero
authors: L
authors: Lauriola
authors: Annunziato
authors: A
authors: Mangiola
authors: Carmelo
authors: C
authors: Anile
authors: Giulio
authors: G
authors: Maira
authors: Laura
authors: L
authors: De Marinis
authors: Antonio
authors: A
authors: Bianchi
mesh_terms: D000236:Adenoma / Q000145:classification / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D000293:Adolescent; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D010911:Pituitary Neoplasms / Q000145:classification / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D011379:Prognosis; D011388:Prolactin / Q000378:metabolism; D012008:Recurrence; D012189:Retrospective Studies; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D000324:Adrenocorticotropic Hormone; D011388:Prolactin