Peripheral neurofibromatosis and peroneal muscular atrophy.

We studied four patients with peripheral neurofibromatosis and a neuropathy that had the clinical characteristics of peroneal muscular atrophy. Nerve conduction velocities were slowed by less than 40% of normal, and electromyography demonstrated denervation. Sural nerve biopsies from two patients, which were macroscopically free of nerve sheath tumors, were studied by recording the compound action potentials in vitro and by morphometry. These studies demonstrated a chronic axonal neuropathy with reactive Schwann cell changes. Peroneal muscular atrophy in association with neurofibromatosis may be due to progressive neuronal degeneration and may represent another, uncommon manifestation of peripheral neurofibromatosis.