A Case of Primary Accessory Breast Cancer in a Male

Abstract

We herein report on a very rare case of primary accessory breast carcinoma in the axilla of a male. A 64-year-old man was admitted to our hospital for treatment of an axillary tumor, measuring 13×13×11 cm in the right axillary area. Core needle biopsy revealed invasive adenocarcinoma. Immunohistochemical findings for tumor cells were positive for both ER and PgR positive and Her 2, CK5/6, CEA, EGFR were negative. CT, MRI and FDG-PET/CT examinations showed neither tumors in any other organ nor apparent lymph node swelling in the right axillary area. We suspected an accessory breast cancer or lymph node involvement from occult breast cancer. The patient underwent a mastectomy with axillary lymph node dissection. Phathological findings of the resected mass was a low grade adenocarcinoma with tubular formation. After surgery, FEC₁₀₀×4 and weekly pacritaxel×12 followed by tamoxifen was performed as adjuvant therapy. There has been no evidence of recurrence for 8 months after the surgery.