Metastatic renal cell carcinoma mimicking a schwannoma in a dorsal root ganglion: case report.

Peripheral nerve tumors are soft-tissue tumors that can occur in any nerve throughout the body. The majority of peripheral nerve tumors arise from elements of the nerve sheath with the two most common being neurofibromas and schwannomas. More than 90% of all peripheral nerve tumors are benign. When there is peripheral nerve involvement in metastatic carcinoma, it is often via contiguous spread from the primary mass; hematogenous seeding to a peripheral nerve is seldom seen. In this report the authors describe the even rarer case of metastatic renal cell carcinoma mimicking a schwannoma in a dorsal root ganglion. Cases from the literature show the rarity of this finding and its late clinical appearance. Given that survival in patients with metastatic carcinoma continues to increase, dorsal root ganglion metastasis may become more common over time.