A Rare Case of Sural Schwannoma With Involvement of the Medial Sural Cutaneous Nerve: A Case Report and Literature Review

Schwannomas are benign tumors derived from Schwann cells, typically occurring in the head, neck, and upper extremities, but are less frequent in the lower extremities. They can arise sporadically or from genetic conditions such as neurofibromatosis type 2, associated with <i>NF2</i> gene mutations. This report details the case of a 57-year-old female with a two-year history of a painless, slowly growing mass in the posterior aspect of the right proximal cruris. Physical examination revealed a 2 cm, elastic-hard, mobile, non-tender mass with a positive Tinel's sign. Ultrasound and magnetic resonance imaging suggested a benign nerve sheath tumor characterized by hypoechoic features. The performed surgery revealed that the tumor involved the medial sural cutaneous nerve. Histologic analysis confirmed the diagnosis of schwannoma, showing typical Antoni A and Antoni B regions. Postoperative recovery was uneventful, with no recurrence or neurological deficits at the two-month follow-up. This case demonstrates an unusual localization of a sural schwannoma and highlights the importance of precise physical examination and imaging to diagnose schwannomas accurately. Clinicians should consider schwannoma as a differential diagnosis in patients presenting with slow-growing palpable masses in the lower extremities.