Metachronous bilateral ectopic breast carcinoma in the axilla: A case report and literature review.

Bilateral ectopic axillary breast carcinoma is extremely rare. Here, we report the case of a 68-year-old woman who presented with a palpable mass in the right axilla. After ectopic breast carcinoma diagnosis, the patient underwent partial mastectomy and sentinel lymph node biopsy, followed by radiotherapy of the whole breast. Adjuvant endocrine therapy was administered for 5 years. Seven years after the first carcinoma diagnosis, the patient noticed a second tumor in the left axilla by herself at the age of 75 years. Core needle biopsy revealed second primary breast carcinoma of the axilla. She underwent partial mastectomy and sentinel lymph node biopsy followed by chemotherapy, radiotherapy, and endocrine therapy. No recurrence has been observed so far. Therefore, ectopic breast carcinoma should be treated as typical breast carcinoma.