Interfascicular Renal Cell Carcinoma Metastasis to the Ulnar Nerve: A Case Report

Metastatic solid tumors to the hand and peripheral nerves are exceedingly rare independent occurrences. Their occurrence together has never been reported in the literature.

We present a case report of a 69 year old male with a previous history of renal cell carcinoma (RCC) presenting with a rapidly-growing painful mass located at the right volar ulnar wrist, found to have endoneural solid tumor metastatic RCC to the ulnar nerve.

Preoperative MRI imaging of the wrist revealed a heterogeneous mass on the volar aspect of the wrist extending along the length of the ulnar artery and nerve to the level of Guyon's canal. Pathologic examination of an incisional biopsy of the mass was consistent with metastatic renal clear cell carcinoma cells, which were infiltrating nerve and surrounding soft tissue. The patient underwent local radiation therapy to the wrist and hand with interval decrease in size of the mass and symptom improvement.

Solid tumor metastasis, although exceedingly rare, must be considered in the differential diagnosis of a patient with previous cancer history presenting with a wrist or hand mass associated with peripheral neuropathy.