We report a case of carcinoma originating from accessory breast tissue of axilla and review 33 reported cases of carcinoma in heterotopic breast tissue. Although the incidence of accessory breast cancer is not high, early diagnosis and treatment are necessary, keeping in mind the possibility of this carcinoma when subcutaneous nodules of uncertain origin are found around the breast. Surgical treatment which must at least include wide local extirpation including the surrounding tissues and dissection of the axillary lymph nodes is necessary and adjunctive chemotherapy and irradiation appear to be useful.