Malignant Peripheral Nerve Sheath Tumor of the Cervical Spine Treated with Surgical Resection Followed by X-ray Radiotherapy or Carbon Ion Radiotherapy: A Report of Three Cases

INTRODUCTION: Spinal malignant peripheral nerve sheath tumors (MPNSTs) are extremely rare. Because of vital surroundings, en bloc resection can be difficult in MPNSTs of the cervical spine. Herein, we report three cases of MPNST followed by radiotherapy or carbon ion radiotherapy (CIRT) after surgery. TECHNICAL NOTE: In case 1, the patient underwent subtotal resection from both a posterior and anterior approach following by adjuvant X-ray radiotherapy. The patient died 13 years after surgery due to liver cancer unrelated to MPNST. In case 2, recurrence spread to the spinal canal in 10 months after primary CIRT. The patient underwent resection of the spinal canal lesion with the residual lesion treated by additional CIRT. Recurrence could be controlled for at least 1 year. In case 3, the patient underwent partial resection for the spinal canal lesion with the residual lesion treated by CIRT. Intradural and extradural recurrences from outside of the CIRT field were observed at 3 years after surgery. CONCLUSIONS: Complete resection and adjuvant X-ray radiotherapy would be an effective treatment for MPNST of the cervical spine, even if en bloc resection with a wide margin is impossible. CIRT for the residual tumor after incomplete resection may have the potential to be an additional treatment option; however, further investigation is warranted.