Linear Accelerator-Based Stereotactic Radiosurgery for Cranial Intraparenchymal Metastasis of a Malignant Peripheral Nerve Sheath Tumor: Case Report and Review of the Literature

Brain metastasis and intracranial leptomeningeal metastasis from malignant peripheral nerve sheath tumors: illustrative cases

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft-tissue tumors. Intracranial metastasis from MPNSTs is quite rare.

OBSERVATIONS

The authors report on a 73-year-old male whose MPNST metastasized to the brain and a 32-year-old male with leptomeningeal metastasis from MPNST and review 41 cases of MPNST that developed intracranial metastasis, as reported in the literature.

LESSONS

Brain metastasis and leptomeningeal metastasis of MPNSTs show different clinical courses and require pathology-specific treatment.

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

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.

Intracranial metastasis from a malignant peripheral nerve sheath tumor in a patient with neurofibromatosis type 1: A case study and literature review

INTRODUCTION

Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are a rare type of soft tissue sarcoma. While these tumors often metastasize, intracranial metastases of MPNSTs have only been rarely noted.

METHODS

Using Pubmed, Google Scholar, and Science Direct we conducted a systematic review of the literature to identify all reported cases of MPNSTs with metastases to the brain since the inception of these databases through January 2020. Data were extracted and data analysis was completed using python statistical packages.

RESULTS

Only 26 cases (including present study) of MPNSTs resulting in intracranial metastases have been reported in the literature. Eight of these 26 cases occurred in patients who were previously diagnosed with Neurofibromatosis Type 1 (NF1). Additionally, one patient had been previously diagnosed with Neurofibromatosis Type 2 (NF2). The average reported time from diagnosis of a MPNST to the time of diagnosis with intracranial metastasis was 36 months, with a median time of 14 months. The average reported survival time for patients after being diagnosed with intracranial metastasis was 5.9 months. The cases that utilized a combination of therapeutic intervention including surgical resection, radiotherapy and chemotherapy saw the greatest improvement of survival times.

CONCLUSION

MPNSTs with brain metastases are extremely rare and have a poor prognosis with a 6 months median survival after metastasis. While combination therapy is indicated, further studies on treatment are needed to determine survival benefits. Early and effective initial diagnosis of MPNST before brain metastases occurs is likely to give the best chance of increased overall survival.