title: No elevation in long-term breast carcinoma risk for women with fibroadenomas that contain atypical hyperplasia.
abstract: BACKGROUND
  The authors previously showed that women with a fibroadenoma have a relative risk of invasive breast carcinoma of approximately 2.0 compared with women of similar age from the general population. This relative risk approaches 1.0 when family history and proliferative changes in the adjacent parenchyma are removed and rises to > 3.0 if the fibroadenoma has complex histology. The risk for developing breast carcinoma in women with atypical lobular hyperplasia (ALH) and atypical ductal hyperplasia (ADH) or their minimal variants within a fibroadenoma is unknown.
  
  
  METHODS
  The authors conducted a long-term, retrospective cohort study of 1834 women with adequate follow-up who presented with fibroadenoma at three local hospitals between 1950 and 1968. Histology was reviewed using established criteria, and the patients were categorized with ALH, ADH, minimal atypia, or no atypia.
  
  
  RESULTS
  The overall prevalence of ALH or ADH within fibroadenomas was 0.81%. Minimal or true atypia within a fibroadenoma appeared to be correlated with proliferative disease in the adjacent parenchyma but could not predict for the presence there of well-established atypia. Only 7% of women with well-developed atypia developed invasive carcinoma on follow-up. Three women with minimal atypia developed invasive carcinoma.
  
  
  CONCLUSIONS
  In this study of a large cohort of women with fibroadenoma, the authors found that atypia within a fibroadenoma cannot predict for the presence of atypia within adjacent breast parenchyma. They also found that atypia confined to a fibroadenoma does not incur a clinically meaningful risk of future breast carcinoma development greater than that of fibroadenoma alone.
authors.affiliation: Department of Laboratory and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada. carteb@hhsc.ca
authors.forename: B A
authors.initials: BA
authors.lastname: Carter
authors.forename: D L
authors.initials: DL
authors.lastname: Page
authors.forename: P
authors.initials: P
authors.lastname: Schuyler
authors.forename: F F
authors.initials: FF
authors.lastname: Parl
authors.forename: J F
authors.initials: JF
authors.lastname: Simpson
authors.forename: R A
authors.initials: RA
authors.lastname: Jensen
authors.forename: W D
authors.initials: WD
authors.lastname: Dupont
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology; D015331:Cohort Studies; D005260:Female; D018226:Fibroadenoma / Q000150:complications*; D006801:Humans; D006965:Hyperplasia / Q000150:complications; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D014930:Women