SO-01 * PRIMARY INTRADURAL MALIGNANT PERIPHERAL NERVE SHEATH TUMOR: CASE REPORT AND REVIEW

Abstract

Malignant peripheral nerve sheath tumor (MPNST) is a rare sarcoma which is most commonly encountered in the extremities, and is often associated with neurofibromatosis type 1 (NF-1). Primary intradural lesions are rarely reported, particularly in the pediatric population. A 15 year old girl was referred to neurosurgery with 18 months of axial low back pain radiating into her hips and thighs, and 3 months of a House-Brackmann 3 right facial droop associated with left sided impaired pupillary constriction and anisocoria. Neurologic exam was otherwise normal. Genetic testing for NF-1 was negative. Brain imaging was normal. Spine imaging revealed an intradural mass associated with the left L3 nerve root. The patient was taken to surgery for resection of the mass. A lesion intrinsic to that nerve was identified and subtotally resected due to concern for iatrogenic injury. Postoperatively, the patient did not develop any new neurologic deficit. Pathologic diagnosis was grade 3 (FNCLCC score 6 of 8) malignant peripheral nerve sheath tumor. Staging CT/PET revealed 2 additional sites of disease in the nerve roots at C6/7 and C7/T1. Lumbar puncture was negative for malignant cells. The patient has subsequently initiated craniospinal proton beam radiotherapy. MPNSTs constitute 5-10% of all soft tissue sarcomas, with a peak incidence in the 7th decade of life. Up to half of these lesions are found in patients with neurofibromatosis type 1, in whom the peak incidence is in the 3rd or 4th decade. 19 cases of pediatric primary intradural MPNST have been previously reported. Surgical treatment is limited due to inability to achieve en bloc resection with wide margins within the intradural compartment. Outcomes have been poor, with 50% or less survival at 2 years despite aggressive multimodal therapies. Further optimization of adjuvant therapies is necessary to improve outcomes.