Surgical Management of a Giant Sciatic Nerve Schwannoma: A Nerve-Sparing Approach

Abstract

Schwannomas are slow-growing benign tumors arising from Schwann cells, predominantly occurring in the head and neck region. However, extremity schwannomas are rare, occurring in about only 1% of cases. The majority of these tumors are usually smaller, measuring less than 5 cm; however, larger tumors are termed “giant schwannomas.” We report a case of giant schwannoma of the lower limb successfully managed with nerve-sparing surgical excision. A 48-year-old female presented with a 9 6 cm well-defined swelling, firm, smooth on the posterolateral aspect of the left thigh, with tingling and numbness in the left lower limb. In contrast, in magnetic resonance imaging (MRI), the tumor was fusiform, a large, welldefined, heterogeneous enhancing lesion measuring approximately 8.7 6.5 4.8 cm (CC TS AP) with areas of hemorrhage in the posterior aspect of the left lower thigh arising from the sciatic nerve, causing displacement of adjacent muscles without infiltrating or invading the surrounding muscle/bone. Excision biopsy was done and confirmed as a schwannoma. The postoperative course was uneventful without neurological deficit. Schwannomas are the most common peripheral nerve sheath tumors, which are slowgrowing and predominantly located in the head and neck region. Lower extremity localization is rare; however, if present, the maximum diameter is 5 cm as reported in most cases. Clinical presentation may range from asymptomatic to compressive symptoms, sometimes unspecific and unclear symptoms. Radiological evaluation using ultrasound and MRI plays a crucial role in diagnosing these tumors, accurately determining the origin of the lesion, and assessing the surrounding tissue involvement. The recommended treatment is surgical excision/enucleation without causing damage to the involved nerve