[A juvenile case of chronic inflammatory demyelinating polyradiculoneuropathy with severe onion bulb-like change mimicking hereditary neuropathy].

A 15-year-old male developed symmetrical weakness of the limb muscles. He had not had any previous developmental disorders except delayed initiation of walking. Flexion contraction of ankle joint and pes cavus deformity were seen. The cerebrospinal fluid protein concentration was elevated. Nerve conduction study showed severe conduction block and temporal dispersion. A sural nerve biopsy revealed remarkable onion bulb-like changes and perivascular infiltration of inflammatory cells. After high-dose corticosteroid treatment, he showed improvement in muscle strength. Although there were no abnormalities of genes related to hereditary neuropathy, the atypical findings of severe demyelinating changes of peripheral nerves mimicked hereditary neuropathy.