Localized hypertrophic mononeuropathy involving the femoral nerve.

The authors report a case of localized hypertrophic mononeuropathy involving the femoral nerve in a 20-year-old woman referred because of progressive weakness and atrophy of the left thigh. MRI showed an enlarged femoral nerve and biopsies of fascicles displayed a concentric pattern of cells resembling an onion bulb. These cells were positive for epithelial membrane antigen immunostaining and had an incomplete basal lamina.