Paraneoplastic vasculitis of nerve: a remote effect of cancer.

The development of mononeuritis multiplex brought three men to medical attention weeks to months prior to the diagnosis of a malignancy. In each case, sural nerve biopsy exhibited active wallerian degeneration with vasculitis. Two of the men died and at autopsy were found to have clinically unrecognized oat cell carcinoma and carcinomatous sensory neuropathy with brainstem encephalitis. The third patient is still alive but was found to have a lymphoma and has subsequently developed a liposarcoma. The vasculitis in all 3 cases seems limited mainly to the peripheral nervous system. Mononeuritis multiplex due to vasculitis may represent a new remote effect of cancer on the nervous system.