Renal cell carcinomatous meningitis: pathologic and immunohistochemical features.

We report the clinical, radiographic, pathologic, and immunohistochemical features of a patient with widespread meningeal carcinomatosis from renal cell carcinoma. Clear and spindle tumor cell subtypes infiltrated the meninges of the cauda equina, oculomotor nerve, spinal cord, and cerebral hemispheres, forming abortive glandular or tubular aggregates without evidence of parenchymal invasion. Cytokeratin epitopes were labeled immunohistochemically with Cam 5.2 antibodies, but epithelial membrane antigen and neuron-specific enolase were not present.