DUCTAL CARCINOMA IN SITU ARISING WITHIN BREAST FIBROADENOMA: A CASE REPORT AND REVIEW OF THE LITERATURE

Fibroadenoma is the most common benign breast tumor in women under 30. However, carcinoma arising in a fibroadenoma is unusual and very rare, with over 100 cases reported in the literature. Histological diagnosis is usually incidental. We report the case of a 51-year-old perimenopausal patient with a family history of a mother who died of breast cancer. She was admitted with a hard elastic mass in the upper outer quadrant of her left breast. Imaging revealed a heterogeneous nodule with ductal dilatation. A core needle biopsy with four specimens showed a fibroepithelial tumor with atypical ductal hyperplasia. Left breast-conserving surgery was performed for radical treatment. The diagnosis on the specimen was carcinoma in situ of intermediate nuclear grade and massive compact and cribriform type developed on a fibroadenoma. We present this case to raise awareness of this entity and highlight the need for histological evaluation of specific breast masses.