A case of plexiform schwannoma arising from the sciatic, tibial, and peroneal nerves.

Plexiform schwannoma is a rare subtype of schwannoma. In this report, we present a case of plexiform schwannoma arising from the sciatic, tibial, and peroneal nerves. A 54-year-old man presented with a painful palpable mass extending from the left posterior thigh to the calf. Magnetic resonance imaging showed multiple bead-like nodular structures along the sciatic, tibial, and peroneal nerve pathway. The nodular lesions showed uniform signal intensity on T1-weighted imaging. On T2-weighted imaging, each nodule showed an eccentric area of relatively low signal intensity surrounded by an area of higher signal intensity and a low-intensity rim. Plexiform schwannoma or neurofibroma was considered as the preoperative diagnosis. Because of the patient's severe symptoms and strong desire for relief, tumor enucleation of the largest painful nodule was performed, and plexiform schwannoma was confirmed pathologically.