Metastatic renal cell carcinoma presenting as a breast lump in a treated breast cancer patient.

Metastatic malignancy in the breast is uncommon. A 68-year-old woman with a past medical history of breast cancer presented with a lump in the opposite breast. A mammogram suggested a possible benign lump. An ultrasonography-guided core needle biopsy was taken to complete the triple assessment. The histology on the breast core biopsy showed it to be a metastatic renal cell carcinoma. Subsequent computed tomography of the abdomen confirmed a renal primary tumour. The patient was referred to the renal oncologist for palliative treatment.