[A Case of Axillary Accessory Breast Cancer Treated via Latissimus Dorsi Musculocutaneous Flap Reconstruction].

A 46-year-old woman visited our hospital with the chief complaint of left axillary mass enlargement, which she had been aware of for 8 years. Palpation revealed that the mass was 15mm in size. Redness and gathering of the skin were also observed. Mammographic imaging of the left axilla revealed an irregular mass with skin infiltration. Breast ultrasonography revealed a low echo mass in the left axilla, which was continuous from the skin. Core needle biopsy was used to diagnose the tumor as an invasive ductal carcinoma. No other lesions were observed in the breast, and primary lesions were not found in any other organs. The patient was diagnosed with axillary accessory breast cancer and underwent local extensive resection and axillary lymph node dissection. Because the skin defect was widespread, we performed axillary reconstruction using the latissimus dorsi musculocutaneous flap to prevent upper limb contracture. At present, she can move her upper limbs and lymphedema has not been observed. In cases of axillary accessory breast cancer with skin infiltration, reconstruction using the latissimus dorsi musculocutaneous flap can be a useful procedure.