Locally advanced breast cancer arising in the axilla.

Locally advanced breast cancer arising from ectopic axillary breast tissue is an unusual presentation of this malignancy. The work-up and treatment approach pose some unique challenges. We present the case of a 37-year-old female presenting with a left axillary lesion with skin involvement. Radiological studies and biopsy demonstrated an underlying axillary mass compatible with a triple-positive invasive ductal carcinoma of the breast. Following neoadjuvant therapy, the patient underwent nipple-sparing mastectomy with wide local excision of the involved axillary skin and axillary lymph node dissection. Ectopic locally advanced breast cancer can be treated similarly to its orthotopic counterpart, favoring a neoadjuvant therapy approach followed by surgical excision. Special considerations include the local anatomy of the tumor, the extent of surgery and reconstructive options.