Hypertrophic inflammatory neuropathy involving bilateral brachial plexus

BACKGROUND The present case is an example of hypertrophic inflammatory neuropathy (HIN ). This entity is a rare tumor-like, chronic inflammatory, focal or multifo cal, mainly demyelinating neuropathy of unknown origin, most frequently inv olving the brachial plexus. CASE DESCRIPTION The authors describe a 67-year-old man presenting with a nodular mass in hi s right supraclavicular fossa. A nodular mass grossly resembling a schwanno ma originating from a single nerve fascicle was surgically removed from the right C6 spinal nerve. Histologically, endoneurial edema, fibrosis, focal chronic inflammation, and extensive "onion bulb" formation were seen. Elect ron microscopy studies and immunohistochemistry proved that the onion bulb- forming cells were schwannian in nature and that the whorls of onion bulbs surrounded a generally demyelinated axon. Three months following surgery th e patient developed acute painless paralysis of his right biceps brachii mu scle that rapidly reversed; after that he remained neurologically asymptoma tic. MRI revealed multiple fusiform mass lesions involving the brachial ple xus bilaterally. Electrophysiologic studies demonstrated a bilateral, asymm etrical, mainly demyelinating neuropathy involving the brachial plexus; the y failed to reveal any abnormality suggestive of generalized neuropathy. CONCLUSION HIN is different from other focal tumor-like neuropathies and in particular from localized hypertrophic neuropathy (LHN). (C) 1999 by Elsevier Science Inc.