title: Perineurial cell hypertrophic mononeuropathy manifesting as carpal tunnel syndrome.
abstract: A 42-year-old man showed signs and symptoms suggestive of carpal-tunnel syndrome, but EMG showed an isolated motor axon-loss lesion affecting the right median nerve distally. After the MRI revealed a mass in the median nerve, surgical exploration showed a diffusely swollen median motor branch. Biopsy showed a lesion with marked onion-bulb formation composed of perineurial cells as identified by immunohistochemical analyses and electron microscopic examination. Although we previously coined the term "perineurioma" for this condition, re-reviews of our cases do not support the idea that the onion-bulb lesion is a benign tumor; instead, it appears to be reactive hyperplasia. Although rare, electromyographers and neurologists need to be aware of this problem because it is self-limited and does not require surgical resection.
authors: Department of Neurology, Cleveland Clinic Foundation, Ohio 44195.
authors: H
authors: H
authors: Mitsumoto
authors: M L
authors: ML
authors: Estes
authors: A J
authors: AJ
authors: Wilbourn
authors: J E
authors: JE
authors: Culver
mesh_terms: D000328:Adult; D001706:Biopsy; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis*; D003937:Diagnosis, Differential; D004568:Electrodiagnosis; D006801:Humans; D006984:Hypertrophy; D008279:Magnetic Resonance Imaging; D008297:Male; D008475:Median Nerve / Q000473:pathology; D009422:Nervous System Diseases / Q000175:diagnosis / Q000473:pathology