title: Atypical apocrine adenosis of the breast: long-term follow-up in 37 patients.
abstract: BACKGROUND
  Atypical apocrine adenosis is a rare breast lesion in which the cellular population demonstrates cytologic alterations that may be confused with malignancy. The clinical significance and management of atypical apocrine adenosis are unclear because of the lack of long-term follow-up studies.
  
  
  OBJECTIVE
  To determine the breast cancer risk in a retrospective series of patients with atypical apocrine adenosis diagnosed in otherwise benign, breast excisional biopsies.
  
  
  METHODS
  We identified 37 atypical apocrine adenosis cases in the Mayo Benign Breast Disease Cohort (9340 women) between 1967 and 1991 with a blinded pathology rereview. Breast cancer diagnoses subsequent to initial atypical apocrine adenosis biopsy were identified (average follow-up, 14 years).
  
  
  RESULTS
  The mean age at diagnosis of atypical apocrine adenosis in the group was 59 years. Breast carcinoma subsequently developed in 3 women (8%) with atypical apocrine adenosis, diagnosed after follow-up intervals of 4, 12, and 18 years. The tumor from 1 of the 3 cases (33%) was ductal carcinoma in situ, contralateral to the original biopsy, and the other 2 cases (66%) were invasive carcinoma. Ages at the time of diagnosis of atypical apocrine adenosis were 55, 47, and 63 years for those that developed in situ or invasive carcinoma.
  
  
  CONCLUSIONS
  (1) Atypical apocrine adenosis was a rare lesion during the accrual era of our cohort (<1% of cases); (2) women found to have atypical apocrine adenosis were, on average, older than were other patients with benign breast disease, however, there does not seem to be an association with age and risk for developing carcinoma in patients diagnosed with atypical apocrine adenosis, as previously suggested; and (3) atypical apocrine adenosis does not appear to be an aggressive lesion and should not be regarded as a direct histologic precursor to breast carcinoma.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota 55905-0001, USA.
authors.forename: Neil
authors.initials: N
authors.lastname: Fuehrer
authors.forename: Lynn
authors.initials: L
authors.lastname: Hartmann
authors.forename: Amy
authors.initials: A
authors.lastname: Degnim
authors.forename: Teresa
authors.initials: T
authors.lastname: Allers
authors.forename: Robert
authors.initials: R
authors.lastname: Vierkant
authors.forename: Marlene
authors.initials: M
authors.lastname: Frost
authors.forename: Daniel
authors.initials: D
authors.lastname: Visscher
mesh_terms: D000368:Aged; D001050:Apocrine Glands / Q000473:pathology*; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000473:pathology*; D002277:Carcinoma / Q000473:pathology*; D005260:Female; D005348:Fibrocystic Breast Disease / Q000473:pathology*; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D012189:Retrospective Studies; D012306:Risk