Abstract
We report a case of male accessory breast cancer in the left anterior chest wall. A 65-year-old man was treated for a subcutaneous tumor in the left anterior chest wall at a neighborhood clinic. Histopathology of the resected tumor suggested a metastatic carcinoma with neuroendocrine differentiation, and the surgical margin was positive. Systemic examination at our hospital revealed no evidence of a primary malignancy in the skin tumor. Based on the tumor originating on the mammary ridge and some glands possibly suggestive of accessory breast tissue in the tumor, a final diagnosis of accessory breast cancer was made. Therefore, 5 months after the tumorectomy, resection of the residual tumor with axillary lymph node dissection was performed. Immunohistochemical staining demonstrated positive staining for ER and PgR, and negative staining for HER2. No axillary lymph node metastasis was found. Endocrine therapy with tamoxifen was started after the surgery and at present, 24 months since the reoperation, the patient shows no evidence of metastatic lesions. To the best of our knowledge, this is the first case of male accessory breast cancer originating in the left anterior chest wall.
