Paraneoplastic vasculitis of the peripheral nervous system

There are 30 patients with paraneoplastic vasculitic neuropathy in the literature. The disorder typically presents in older men with subacute and occasionally painful neuropathy and a clinical and electrodiagnostic pattern of mononeuropathy multiplex or axonal sensorimotor polyneuropathy. The erythrocyte sedimentation rate and cerebrospinal fluid protein content and cell count are typically elevated, with more than one-third of patient manifesting circulating antibodies to Hu. The commonest associated malignancies are small cell lung cancer and lymphoma although other cancers have been noted. Sural nerve biopsy typically reveals microvasculitis as may muscle tissue in addition to neurogenic features. The vasculitic disorder may be systemic or nonsystemic. Treatment is directed toward the underlying malignancy as well as immune modulatory and immunosuppressant medication alone or in combination for the neuropathy and vasculitic process, with up to one-half of patients demonstrating clinical improvement. Although uncommon, unsuspected patients may continue to worsen and suffer excess morbidity and mortality due to the underlying cancer and neuropathic disorder.