Case Report: Partial neurectomy and limb-sparing treatment for SOX-10 expressing epithelioid malignant nerve sheath tumour of the tibial nerve.

Abstract

INTRODUCTION: Epithelioid-variant malignant peripheral nerve sheath tumours (EMPNST) are rare in veterinary medicine and typically have poor outcomes. Limb-sparing partial neurectomy is used for distal peripheral nerve sheath tumours but has not previously been described for epithelioid variants. CASE DESCRIPTION: An 8.5-year-old neutered male Dobermann presented with non-weight-bearing left pelvic limb lameness and severe pain on hock flexion. CT and ultrasound showed a homogeneously thickened, contrast-enhancing segment of the left tibial nerve with muscle atrophy. Limb-sparing partial neurectomy with 2-cm margins was performed. Histopathology revealed a poorly demarcated infiltrative malignant neoplasm, completely excised. Immunohistochemistry was strongly positive for Sox-10 and negative for S-100. The dog improved rapidly, and at 12- and 24-month follow-ups showed no recurrence or metastasis. CONCLUSION: This case demonstrates an atypical anatomical and histopathological presentation of canine EMPNST and shows that complete limb-sparing partial neurectomy can achieve long-term remission without compromising limb function.