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Histopathology of Fibroadenoma of the Breast

Arno Kuijper MSc, Ellen C.M. Mommers MSc, Elsken van der Wall PhD, Paul J. van Diest PhD
DOI: http://dx.doi.org/10.1309/F523-FMJV-W886-3J38 736-742 First published online: 1 May 2001


The aim of this study was to make a thorough inventory of the histologic features of epithelium and stroma within and adjacent to breast fibroadenomas in 396 cases. Breast fibroadenomas seemed to display a wide spectrum of proliferative and nonproliferative histologic changes. Hyperplasia (excluding mild hyperplasia) within the fibroadenoma was found in 32.3% of cases. Carcinoma in situ (CIS; 5 ductal, 3 lobular) was found in 8 fibroadenomas (2.0%) removed from 6 patients, the youngest of whom was 40 years of age. In 3 cases CIS was not confined to the fibroadenoma, but also involved the adjacent parenchyma. No invasive carcinoma was present within this series. Complex histologic features were seen in 40.4% of cases, mostly in relatively older patients (mean age, 35.4 years). Hyperplasia in adjacent tissue was found in 8.8% of cases, usually in older patients (mean age, 45.5 years). Known risk-elevating lesions in and around breast fibroadenomas occur frequently and mostly in patients older than 35 years. These findings may have consequences for the clinical management of a subgroup of patients with fibroadenoma.

Key Words:
  • Breast
  • Fibroadenoma
  • Histopathology
  • Hyperplasia
  • Ductal carcinoma in situ
  • Lobular carcinoma in situ