Accessory Breast Cancer of the Axilla: A Case Report

We report a case of accessory breast cancer in the right axillary region. A 67-year-old woman visited our department complaining of a lump in the right underarm. We suspected cancer of an accessory breast from the findings of mammography and ultrasonography; a histological diagnosis of breast cancer was obtained by needle biopsy. With a preoperative diagnosis of accessorybreast cancer accompanied by ipsilateral axillary nodal involvement, the patient underwent wide local resection of the right axillary region with lymph-node dissection (level II). Histopathological findings of the resected specimen revealed that the tumor was composed of solid tubular carcinoma with intraductal component, with normal breast tissue in the region adjacent to the tumor. A diagnosis of right axillary accessory breast cancer (pT2, N1, pStage IIb) was confirmed. Postoperative chemotherapy and radiotherapy were administered. At present, 18 months after surgery, no sign of recurrence has been observed.