Fibroadenoma progress to ductal carcinoma in situ, infiltrating ductal carcinoma and lymph node metastasis? Report an unusual case

Fibroadenoma of the breast is the most common benign neoplasm in young women who present with a palpable, movable mass. Malignancy inside fibroadenomas is rare, with reported rates ranging from 0.002% to 0.125%. Carcinoma in situ inside a fibroadenoma is usually found incidentally when tumours are excised. Whether fibroadenoma is a risk factor for breast cancer remains controversial. Due to the rarity of carcinomas inside fibroadenomas, medical institutes have little experience with this phenomenon. We report an unusual case in which progression occurred from benign fibroadenoma to ductal carcinoma in situ, infiltrating ductal carcinoma and lymph node metastasis. A nipple-areolar complex-preserving mastectomy with immediate breast reconstruction with a gel implant and contralateral augmentation was performed. No local recurrence or metastasis was found during 5 years of follow-up.