Intracranial Malignant Peripheral Nerve Sheath Tumors Not Associated with a Cranial Nerve: Systematic Review and Illustrative Case

Abstract

Primary intracranial malignant peripheral nerve sheath tumors (MPNSTs) not associated with cranial nerves are rare and aggressive neoplasms. The rarity of presentation has precluded rigorous analysis of diagnosis, risk factors, treatment, and survival. We analyzed every reported case through exhaustive literature review. In addition, we present our own experience managed with resection, radiotherapy, and first use of targeted therapy in a tumor of this type for a BRAF mutation identified during next-generation sequencing. Two databases, PubMed and Embase, and crossed references were queried for intracranial MPNSTs not associated with a cranial nerve. Extracted variables included demographics, risk factors, tumor characteristics, interventions, and outcomes. Univariate and multivariate analysis was performed to identify factors with survival benefit. A total of 56 patients (including the present case) were included from 743 literature results. There was a male/female ratio of 1.5:1 and mean diagnosis age of 29.7 ± 21.8 years. Seventy-one percent of cases were sporadic and 23% neurofibromatosis type 1 related. Median survival was 29 ± 22.1 months with 1-year survival of 60%. Factors associated on univariate analysis with reduced survival were subtotal resection (P= 0.05), older age (P= 0.023), triton histology (P < 0.001), and early recurrence (≤6 months) (P= 0.018). On multivariate analysis, gross total resection reduced mortality risk (P= 0.011), whereas triton histology (P= 0.017) and infratentorial tumor location (P= 0.037) increased mortality. We present a systematic review of intracranial MPNSTs not associated with a cranial nerve. These tumors have poor prognosis and benefit from aggressive resection, multimodal treatment, and close follow-up. Next-generation sequencing can show molecular alterations for potential targeted therapy.