[An autopsy case of systemic vasculitis associated with hepatitis C virus-related mixed cryoglobulinemia presenting severe peripheral neuropathy].

A 75-year-old man, previously diagnosed as having chronic hepatitis C virus (HCV) infection, suddenly developed left foot drop, followed by progressive motor weakness and sensory disturbance in all of the extremities. Because of an elevated level of the rheumatoid factor (RF), he had been treated with antirheumatic drugs three years before the onset of his neurological symptoms. Within two months, he became unable to walk any more, and was transferred to our hospital. Neurologic examination showed asymmetrical severe muscular weakness and atrophy of all the limbs, and a sensory deficit under the level of the wrists and knees. Livedo reticularis was also noted in bilateral legs. Nerve conduction study revealed severe sensorimotor axonal neuropathy, and muscle biopsy specimens showed necrotizing vasculitis of small arteries in the perimysium. Serological tests indicated type II cryoglobulinemia (monoclonal IgAkappa + polyclonal IgG). A diagnosis of vasculitic neuropathy associated with HCV-related mixed cryoglobulinemia was made. A high-dose intravenous immunoglobulin therapy (IVIg) and a high-dose steroid therapy were not effective, and he died of alveolar hemorrhage probably due to pulmonary vasculitis. Postmortem pathological examination revealed severe vasculitis, accompanied by fibrinoid degeneration and the infiltration of predominant mononuclear cells into the small and medium-sized vascular walls of multiple organs such as the liver, kidney, pancreas and intestine as well as the peripheral nerves and skeletal muscles. A severe loss of myelinated fibers were also observed in the multiple peripheral nerves examined. We emphasize that patients with HCV infection and mixed cryoglobulinemia may develop severe systemic vasculitis resembling polyarteritis nodosa leading to often life-threatening polyvisceral failure, particularly in patients showing progressive mononeuropathy multiplex.