Solitary schwannoma of the sural nerve: An unusual clinical presentation.

Schwannomas may arise from any peripheral nerve containing Schwann cells. However, sural nerve schwannoma is extremely rare. In this study, a case of solitary schwannoma originating from the sural nerve in a 42-year-old male is presented. Physical examination revealed a 3-cm, elastic-hard, mobile, non-tender mass, while neurovascular examinations, including Tinel's sign, were normal. Magnetic resonance imaging revealed an oval-shaped subcutaneous mass with iso-signal intensity relative to skeletal muscle on T1-weighted sequences. T2-weighted spectral presaturation with inversion recovery sequences showed higher signal intensity peripherally and lower signal intensity centrally, representing a target sign. Contrast-enhanced T1-weighted sequences demonstrated a marked central enhancement of the mass. The tumor was completely enucleated using an intracapsular technique. Histological examination confirmed the diagnosis of a schwannoma, consisting mainly of Antoni A tissue. The patient had no evidence of local recurrence and no neurological deficit at the final follow-up. Although rare, schwannoma should be considered in the differential diagnosis of a well-defined, oval, subcutaneous mass in the posterior aspect of the lower leg.