Radiotherapy-induced malignant peripheral nerve sheath tumor of the cauda equina.

Study Design: Case report.

Objectives: To report a rare case of radiation-induced malignant peripheral nerve sheath tumor of the cauda equina 10 years after treatment for testicular seminoma.

Summary Of Background Data: Development of malignant peripheral nerve sheath tumor after irradiation is well recognized and often associated with a dismal prognosis. There have been isolated reports of malignant peripheral nerve sheath tumor developing in sites of previous irradiation for testicular seminoma.

Methods: Retrospective review of case records and imaging.

Results: A 38-year-old man presented with signs of cauda equina syndrome. Ten years previously, he had undergone right radical inguinal orchidectomy and adjuvant para-aortic radiotherapy as treatment for Stage I testicular seminoma. Magnetic resonance imaging demonstrated an inoperable intra- and extradural tumor leading to significant cauda equina compression. CT-guided biopsy revealed a diagnosis of malignant peripheral nerve sheath tumor, most likely due to previous radiotherapy. His clinical condition did not improve, and he underwent a course of palliative chemotherapy.

Conclusions: Postirradiation malignant peripheral nerve sheath tumors are rare and occur in a population at high risk of developing second malignancies. The authors report the fourth case resulting from adjuvant radiotherapy for testicular seminoma, with the present report being the first report of extensive intradural tumor leading to cauda equina syndrome.