Paraneoplastic vasculitis of the peripheral nervous system.

Paraneoplastic vasculitic neuropathy (PVN) is a rare paraneoplastic syndrome characterized by non-systemic subacute vasculitic neuropathy. The two cancers most commonly associated with PVN are small cell lung cancer (SCLC) and lymphomas. Neuropathy varies from mononeurotherapy multiplex to symmetrical polyneuropathy. Two helpful laboratory abnormalities are a high erythrocyte sedimentation rate (ESR) and high cerebro spinal fluid (CSF) protein content. Axonal neuropathy is the characteristic finding in electrophysiological studies. Nerve biopsy is crucial to document microvasculitis. Recognition of this entity is important because of its potential treatability. Unlike other paraneoplastic syndromes, anti-cancer chemotherapy and immunotherapy for vasculitis are both effective in this disorder.