Primary infiltrating ductal carcinoma arising in aberrant breast tissue of the axilla: a rare entity. Report of a case.

A 52-year-old woman presented with a palpable nodule in the right axilla. Physical examination revealed a 2.5 x 2.5 cm, nontender, firm, brownish, and peripherally hyperemic mass with overlying skin retraction on the right anterior axillary fold. Bilateral mammogram was negative. Ultrasonography of the right axillary region showed a 1.8 x 1.1 cm, poorly defined hypoechoic mass with irregular margins and posterior acoustic shadowing. Fine-needle aspiration biopsy of the mass revealed malignant epithelial cells. The patient underwent a wide local excision of the right axillary lesion with en bloc axillary lymph node dissection. Histopathological examination revealed an infiltrating ductal carcinoma. Here we report this case of carcinoma originating from aberrant breast tissue in the axilla. It is suggested that subcutaneous lesions of uncertain origin around the periphery of the breast should be suspected for breast carcinoma and treated appropriately.