Age-stratified incidence of unsuspected mammary carcinoma in women with fibroadenoma.

Fibroadenomas (FA) are benign neoplasms with a known albeit rare association with mammary carcinoma (MC). Incompletely explored, however, are 1) the statistical relationship of associated FA/MC with patient age and 2) the microscopic spatial relationship of associated FA/ MC. Pathology records of 1,715 patients with FA, excised over a nine-year period, were reviewed. In 59 patients concomitant diagnoses of FA and MC were rendered. In 40 of these patients MC was clinically unsuspected, signs and symptoms being attributable to the FA. Data were age stratified and slides were reviewed to identify the precise histologic association of FA and MC. Women aged 50 years and older had a statistically significant increased association of FA and MC as compared to their younger counterparts (4.1% vs 1.5%; P = .003). MC complicating FA was in situ or invasive (82.5% vs 17.5%), of ductal, lobular, or combined type (40% vs 52.5% vs 7.5%), and half of the MC were restricted to the "normal" mammary tissue surrounding the FA.