[Child case of chronic inflammatory demyelinating polyneuropathy showing phagocytic myelinolysis and regenerative changes on electron microscopic analysis of the sural nerve].

We reported a 9-year-old boy with chronic inflammatory demyelinating polyneuropathy (CIDP) showing characteristic electron microscopic study findings on a sural nerve biopsy. He came to our hospital because of muscle weakness progressing slowly for 2 years. He developed distal muscle weakness and areflexia. Cerebrospinal fluid protein was elevated without pleocytosis. Moter conduction velocities were reduced. Partial conduction block and abnormal temporal dispersion were present. The electron microscopic findings on a sural nerve biopsy comprised both active demyelinating lesions, i.e., macrophages were peeling away the myelin lamellae and phagocytosing some myelin debris, and remyelinating lesions with onion bulb formations. Some findings mimic electron microscopic changes in Guillain-Barré syndrome, although tests for the known anti-ganglioside antibodies were negative. So, he was diagnosed as having definite CIDP and prednisolone with gamma-globulin infusion was effective to ameliorate his symptoms.