Two cases of carcinoma involving ectopic breast tissue are reported, along with a review of the Japanese literature. A total of 65 cases of ectopic breast cancer have been reported; 59 of which occurred in the axilla. Total mastectomy with axillary dissection was performed in 29 cases, and tumor excision with or without nodal dissection was done in 30 cases. Outcome was known in 33 cases, and 5 cases had recurred at the time of this writing. Although the prognosis of ectopic breast cancer was difficult to establish with the limited follow-up data, all the 5 cases in our series with recurrence had axillary lymph node metastases at the time of surgery. Therefore, the complete excision of ectopic breast tissue with nodal dissection, and subsequent chemoendocrine therapy, especially in node-positive patients, is recommended as the treatment of choice.