Fibroadenomas are a type of benign tumor that occur in young women below the age of 35 years old. The tumors are the second most common type of tumor after fibrocystic disease. The chance of carcinoma arising in a fibroadenoma is extremely low. To date, <130 such cases have been reported. Previous studies have reported that fibroadenomas can evolve into a number of different types of malignancy. The present study is the first to describe a case of bilateral primary breast cancer with a unilateral invasive ductal carcinoma within a fibroadenoma. The current study presents a case of a 48-year-old female who presented with 2 stiff lumps on bilateral breasts, diagnosed as bilateral breast carcinoma, with a unilateral invasive ductal carcinoma within a fibroadenoma in the right breast. The patient underwent a bilateral mastectomy and subsequently received 4 cycles of chemotherapy (epirubicin, 60 mg/m2 and cyclophosphamide, 600 mg/m2) every 21 days, followed by 4 cycles of docetaxel chemotherapy (100 mg/m2) every 21 days. The patient then received maintenance endocrine therapy (tamoxifen, 20 mg, twice daily) for 19 months. The patient was followed up every 3 months, and at the last follow-up examination in May 2015, the patient exhibited no signs of recurrence.
Keywords: breast cancer; fibroadenoma.