Case report 828: Plexiform neurofibroma of the tibial nerve invading the medial and lateral gastrocnemius muscles and plantaris muscle.

A 5-year-old boy presented with a several-year history of swelling of his calf and muscular weakness. MRI demonstrated abnormal signal and diffuse enlargement of the gastrocnemius muscle. Pathological examination revealed plexiform neurofibroma, and the diagnosis of neurofibromatosis was subsequently made. The manifestations of neurofibromatosis and the peripheral nerve sheath tumors encountered in this disease are discussed. Special attention is paid to the MR features of the plexiform neurofibroma which is characteristic of this disorder.