According to clinical and MR findings, a diagnosis of peripheral nerve sheath tumor of the sciatic nerve was made.

An enhancing fusiform mass in continuity with a neurovascular bundle is virtually diagnostic for peripheral nerve sheath tumor. Target sign, as shown in the present case, was previously assumed to be pathognomonic of neurofibroma; however, it has been observed in both neurofibromas and schwannomas and has even been reported in malignant peripheral nerve sheath tumors.