A mammary nodule mimicking breast cancer.

Metastases to the breast from extramammary tumors are rare. Several clinical, radiologic, and histologic signs can help to distinguish metastases from breast primary tumors. In the present study, we present a case of a left-sided breast metastasis from renal cancer in a 44-year-old woman whose clinical presentation was a mammary nodule in the upper internal quadrant. The patient underwent quadrantectomy with sentinel lymph node biopsy. The histology revealed a clear cell carcinoma. On computed tomography scan a 5×8-cm left renal mass with pulmonary, liver, and intrapericardial nodules was found. The patient underwent palliative care and died after 4 months. Metastasis to the breast is rare, but all of those clinical, radiologic, and histologic signs more typical of extramammary malignancies should always be considered in order to choose the best treatment strategy.