Multiple intramuscular metastases 15 years after radical nephrectomy in a patient with stage IV renal cell carcinoma.

We report an 81-year-old man with late recurrent multiple metastases in skeletal muscles 15 years after radical nephrectomy was carried out for stage IV renal cell carcinoma (RCC). The tumors were located in the left triceps muscle and the brachioradial muscle. We performed surgical resections of both tumors, and histological analysis revealed that they were both metastatic RCC of the clear-cell type. In this case report, we discuss the characteristics and differential diagnosis of this tumor on magnetic resonance imaging, and we also refer to the rarity of muscle metastasis and the unpredictable tendency of this tumor to remain dormant for long periods.