Renal medullary carcinoma metastatic to the orbit: a clinicopathologic report.

A 39-year-old black man with sickle cell trait presented with a rapidly progressive, painful proptosis of the left eye. A computed tomographic scan was interpreted as revealing a cavernous hemangioma. Medial orbitotomy revealed a hard, gray mass supranasal to the optic nerve and invading the medial rectus muscle. Intraoperative frozen section specimens were read initially by the pathologist as metastatic adenocarcinoma. On gross examination, the conspicuous hemorrhage, necrosis, and bright yellow color characteristic of renal cell carcinoma were not present. Final pathologic analysis of the orbital lesion revealed metastatic renal medullary cell carcinoma. The primary lesion was located in the right kidney. Renal medullary carcinoma is a rare tumor, often affecting young individuals with sickle cell trait or disease. We report the first confirmed case of renal medullary carcinoma metastatic to the orbit with orbital symptoms preceding the diagnosis of the primary tumor.