AB147. SOH23ABS_178. Atypical lobular hyperplasia in a fibroadenoma a case report

Background: Fibroadenomas represent benign pathological entities composed of epithelial and non-epithelial components. Although the cytologic features of fibroadenomas are well established, cases of atypia within these lesions have been reported.

Methods: We present the case of a 28-year-old female with a 18-month history of three painless lumps in the upper outer region of left breast, measuring 17, 14 and 11 mm. Clinical features were suspicious for fibroadenomas, however following ultrasound evaluation, it was deemed appropriate to undertake tissue sampling of each mass to establish a diagnosis.

Results: A needle core biopsy of each lesion was undertaken which demonstrated a focus of atypical lobular hyperplasia in the 11 mm mass, and tissue consistent with benign fibroadenoma in the remaining two. The patient subsequently underwent surgical excision of each lesion.

Conclusions: Atypical lobular hyperplasia is as a high-risk precursor lesion due to its association with and potential to progress to ductal carcinoma in situ (DCIS) as well as invasive carcinoma. Transformation from fibroadenoma to cancer is rare, regression or resolution is frequent to this end supporting a conservative approach towards follow-up and management. This case highlights a rare example of such atypia requiring surgical excision in an otherwise benign breast entity.

Keywords: Breast; cancer; fibroadenoma; hyperplasia; recurrence