A giant guteal schwannoma with extension into the pelvis: a case report

Schwannomas are uncommon slow growing tumours arising from the nerve sheath or Schwann cell.

To report a case and the surgical removal of a giant complex schwannoma and to highlight the value of extensive investigations including a preoperative histologic diagnosis in the successful surgical management of uncommon large benign tumours.

A 39-year-old man presented with a 15-year history of a large mass in the right gluteal region. He was clinically evaluated, subjected to imaging studies and surgery.

Clinical examination revealed a 40 cm by 60 cm mass in the right gluteal region and continuous with a 25 cm by 15 cm pelvic mass. The ultrasound scan revealed a very complex (mixed solid and fluid containing) gluteal mass with extension to the pelvis. The CT scan showed a very large, well defined lobulated tumour with cystic spaces and enhancing nodules. The tumour extended through the ischiadic foramen into the pelvis and posteriorly into the thigh muscles. A Doppler scan of the pelvic vessels revealed that the right common and internal iliac arteries were both compressed but not occluded. An incisional biopsy was reported as a Schwannoma with xanthomatous changes and an immuno histochemistry profile of S-100+, Ki-67+ (less than 1% of the cells). A right foot drop following the surgery responded to physiotherapy. The duration of total hospital stay was 12 weeks.

The staged excision of large and complex schwannomas is safe. It is essential that a preoperative histological diagnosis is made to establish that the tumor is truly benign.