Metastatic renal cell carcinoma presenting as a breast mass in a woman with history of primary breast cancer.

Metastatic extramammary breast tumours are uncommon and differential diagnosis with primary breast carcinoma may prove to be difficult. We report a case of a metastasis of a renal cell cancer in the breast in a woman with a history of primary breast cancer. On follow-up of her breast carcinoma, a lump was detected via mammography and ultrasound. Core needle biopsy revealed a metastatic extramammary lesion originating from an asymptomatic renal cell carcinoma. We conclude that the diagnosis of metastasis to the breast from extramammary tumours is important to avoid unnecessary surgery and insure proper treatment of the primary disease.