Rare metastasis of renal cell carcinoma to the breast: a case report

Renal cell carcinoma is an aggressive urological malignancy, accounting for 2%-3% of adult cancers and over 90% of renal cancers. While renal cell carcinoma commonly metastasizes to organs such as the lungs, bones, and liver, breast metastasis is rare, comprising only 0.5% to 2% of all breast neoplasms. This case report describes a 54-year-old female with a history of RCC who developed a metastatic lesion in her breast six years after radical nephrectomy. The lesion, initially detected via routine imaging, was confirmed as renal cell carcinoma through histopathology and immunohistochemistry. A wide local excision was performed, avoiding unnecessary axillary surgery. This case highlights the need for meticulous diagnostic evaluation to distinguish between primary breast carcinoma and metastatic disease, particularly in patients with a history of renal cell carcinoma. The rarity of renal cell carcinoma metastasis to the breast calls for further research to guide appropriate management.