Schwannoma of Foot and Ankle: Seven Case Reports and Literature Review.

ABSTRACT

BACKGROUND: Schwannoma is most often grown on the trunk, upper and lower extremities, and head and neck, but rarely on the foot. This study aimed to reveal clinical presentations, histopathology and treatment options for schwannoma of the foot. MATERIALS AND METHODS: Seven schwannomas out of 174 soft-tissue tumors on the foot and ankle were retrieved from our Institute in a 3-year period, and 42 schwannomas on the foot and ankle in the literature in a 30-year period were reviewed. RESULTS: The incidence of schwannoma of foot was found to be 4.0%. The patient age ranged from 8 to 84 years, with a mean of 47.4 years. More than 80% of tumors were located on the ankle, heel and plantar aspect. Overall, 77.6% of patients complained about a painful mass. Magnetic resonance imaging revealed a well-circumscribed, round or ovoid mass with iso-intensity signal compared with surrounding neuromuscular tissues on T1-weighted images and hyper-intensity signal on T2. Forty-eight out of 49 patients were treated with surgical excision or enucleation without recurrence in follow-up from 2 months to 4 years. Histologically, schwannoma was composed of hypercellular Antoni A zone with palisaded spindle cells with strong immunostaining for S-100 and hypocellular Antoni B zone with vascularization in myxoid stroma. CONCLUSION: Schwannoma of the foot and ankle is a rare, painful, indurated tumor. Magnetic resonance imaging reveals the location, size, texture and relationships with surrounding neuromuscular structures. Surgical excision is the primary treatment option with excellent outcome.