Perineuroma, rare in children, presents as a painless mononeuropathy of a major nerve trunk. Resection of the lesion with end-to-end sural nerve grafting appears to be the treatment of choice. This technique is not recommended if the unhealthy segment of nerve is too long or if spinal roots are involved. However, in children, reports of direct MR evaluation of nerve trunks and of the exiting nerve roots are limited. We report a 7-year-old girl with an intramural sciatic nerve perineuroma in whom the diagnosis was made by MRI and confirmed by biopsy. The MR protocol combining 3-D T2-W STIR SPACE, fat-saturated gadolinium-enhanced T1-W images, and diffusion tensor imaging with tractography was a valuable tool for depicting peripheral nerve and roots in order to plan surgical treatment.