2019 Volume 28 Issue 1 Pages 53-57
Fibroadenoma (FA) is a common benign breast tumor, and carcinoma arising within an FA is very rare. We encountered a case of ductal carcinoma in situ (DCIS) that was mainly positioned in the epithelium of an FA. The patient was a ６１-year-old woman with a 10-mm left breast tumor. Mammography and ultrasonography examinations showed a tumor with a largely distinct margin and calcification between the tumor and the nipple. A core needle biopsy from the tumor demonstrated DCIS with stromal hyperplasia. Fine-needle aspiration cytology from a low echoic area with echogenic spots allowed for a diagnosis of malignancy. A partial mastectomy and sentinel node biopsy were performed under a diagnosis of DCIS with ductal spread toward the nipple. The pathological examination revealed an FA with DCIS largely replacing its epithelium and intraductal carcinoma outside the FA. Detailed evaluations of the tumor and the extratumoral findings were useful for the diagnosis of the tumor.
