[Localized hypertrophic neuropathy (LHN) of the brachial plexus: diagnosis and presurgical evaluation with MRI].

The authors report a case of localized hypertrophic neuropathy diagnosed by MRI. This 10-year-old girl presented with painless progressive deltoid atrophy. Electrodiagnostic studies demonstrated chronic denervation. An MRI performed with T1, T2, T1 with gadolinium and fat saturation sequences showed a linear 5-cm long segment of hypertrophic brachial plexus cord, with moderate high T2, intermediate T1 signal, and marked post-Gadolinium enhancement. Progressive improvement followed surgical resection with nerve graft repair. Histological study confirmed LHN (perineurial cell proliferation), a rare cause of peripheral neurological deficit. MRI findings may suggest LHN, that should be suspected as well as peripheral nerve compression or tumor; inflammatory neuritis and idiopathic lesion (with normal MRI findings) remain a diagnosis of exclusion. MR aids in the precise localization of the lesion before surgery.