足関節外側不安定症における腓腹神経シュワン腫：症例報告

Schwannomas are benign encapsulated nerve sheath tumors that are rarely found in the lower extremity. We report a unique case of a 65-year-old woman presenting with chronic lateral ankle instability and a palpable mass posterior to the lateral malleolus. Magnetic resonance imaging revealed an 11 by 6 by 10 mm lesion contiguous with the sural nerve. The mass was excised via meticulous enucleation with nerve preservation. Histopathology confirmed a cellular schwannoma. The patient underwent concurrent ankle arthroscopy and lateral ligament repair, thereby achieving complete resolution of symptoms and return to function at 6 months. This is the first reported case of a sural nerve schwannoma associated with chronic lateral ankle instability.