Localized hypertrophic neuropathy of the sciatic nerve in children: MRI findings.

Abstract : BACKGROUND: Localized hypertrophic neuropathy (LHN) of the sciatic nerve in children is a rare condition characterized by a painless neurological deficit in the sciatic nerve territory. OBJECTIVE: To demonstrate the role of MRI using a specific protocol and describe the primary findings in LHN. MATERIALS AND METHODS: Imaging in four children (age 2 years to 12 years) is presented. All children presented with lower limb asymmetry. Three had a steppage gait. LHN was confirmed by electrophysiological studies and by MRI of the whole sciatic nerve with a dedicated protocol covering the lumbar spine and the lower limb. RESULTS: There were four direct MRI findings: (1) linear and focal hypertrophy with progressive enlargement of a peripheral nerve or plexus diameter, (2) abnormal hyperintensity of the nerve on T2-weighted images, (3) preserved fascicular configuration, and (4) variable enhancement after intravenous gadolinium administration. In addition there were atrophy and fatty infiltration of innervated muscles. MRI was helpful for determining the extent of lesions and in excluding peripheral nerve compression or tumour. CONCLUSION: MRI of the whole sciatic nerve is the method of choice for diagnosing LHN of the sciatic nerve.