When "peripheral" Becomes "central": Primary and Secondary Malignant Intracerebral Nerve Sheath Tumor: A Case Report and a Systematic Review

Abstract

BACKGROUND: The intracerebral occurrence of malignant peripheral nerve sheath tumors (MPNSTs) is exceedingly rare, and despite aggressive treatments, local recurrence and poor prognosis are very frequent. Like other brain tumors, these tumors could be primary or secondary, making the term "peripheral"an imprecise term for a primary brain tumor. OBJECTIVE: To analyze the reported cases of primary and secondary cerebral MPSNTs in terms of diagnosis, treatment, and overall survival. Additionally, we present a case of malignant intracerebral nerve sheath tumor (MINST) treated with radical surgery and radiotherapy. METHODS: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, one database (PubMed) and crossed references were queried for MPNST with brain metastasis and primary MINSTs from 1971 to 2020. Data regarding demographic features, primary tumor site, risk factors, brain location of the lesion, treatment applied, and overall survival were extracted. RESULTS: A total of 55 patients were selected (including the reported case): 29 patients were secondary brain MPNST and 26 patients were primary MINST. The mean age was 41.8 ± 22 and 31.2 ± 23 yr, respectively. All brain metastases of MPNST (100%) had a primary tumor elsewhere in the body at the time of diagnosis. The overall survival was significantly shorter in patients with a secondary brain MPNST compared to MINST (P =. 002). CONCLUSION: We present a comprehensive analysis of every reported primary and secondary intracerebral MPNST. The prognosis in terms of survival is worst in the last one despite aggressive treatment. The lack of a primary MPNST in screening tests is sufficient to confirm a MINST at time of diagnosis.