Malignant intracerebral nerve sheath tumor in a patient with Noonan syndrome: illustrative case

Callum M Allison; Syed Shumon; Abhijit Joshi; Annelies Quaegebeur; Georges Sinclair; Surash Surash

doi:10.3171/CASE21146

Malignant intracerebral nerve sheath tumor in a patient with Noonan syndrome: illustrative case

J Neurosurg Case Lessons. 2021 Jun 28;1(26):CASE21146. doi: 10.3171/CASE21146.

Authors

Callum M Allison^{1

2}, Syed Shumon¹, Abhijit Joshi³, Annelies Quaegebeur⁴, Georges Sinclair^{5

6}, Surash Surash¹

Affiliations

¹ Departments of Neurosurgery and.
² Pathology, Royal Victoria Infirmary, Newcastle Upon Tyne, United Kingdom.
³ Department of Neurosurgery, Bezmialem Vakif University Hospital, Istanbul, Turkey; and.
⁴ Division of Neuropathology, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, London, United Kingdom.
⁵ Newcastle University Medical School, Newcastle Upon Tyne, United Kingdom.
⁶ Department of Oncology, James Cook University Hospital, Middlesbrough, United Kingdom.

Abstract

Background: Malignant peripheral nerve sheath tumors (MPNSTs) within the neuroaxis are rare, usually arising from peripheral and cranial nerves. Even more scarce are cranial subclassifications of MPNSTs termed "malignant intracerebral nerve sheath tumors" (MINSTs). These tumors are aggressive, with a strong tendency for metastasis. With this presentation, alongside resistance to adjunctive therapy, complete excision is the mainstay of treatment, although it is often insufficient, resulting in a high rate of mortality.

Observations: The authors report the case of an adult patient with a history of Noonan syndrome (NS) presenting with slowly progressive right-sided hemiparesis and right-sided focal motor seizures. Despite initial imaging and histology suggesting a left frontal lobe high-grade intrinsic tumor typical of a glioblastoma, subsequent molecular analysis confirmed a diagnosis of MINST. The patient's neurological condition improved after gross-total resection and adjuvant chemo-radiation; he remains on follow-up.

Lessons: MINSTs are rare neoplasms with a poor prognosis; management options are limited, with surgery being the cornerstone of treatment. Reports on rare tumors such as this will increase awareness of this particular pathology and disclose clinical experience. In this case, the authors were unable to establish a definite cause-and-effect relation between NS and MINST. Nevertheless, it remains the first reported case in the literature.

Keywords: NF-1 = neurofibromatosis-1; CNS = central nervous system; GFAP = glial fibrillary acidic protein; GTR = gross-total resection; LL = lower limb; MAPK = mitogen-activated protein kinase; MINST = malignant intracerebral nerve sheath tumor; MPNST = malignant peripheral nerve sheath tumor; MRI = magnetic resonance imaging; NS = Noonan syndrome; TERT = telomerase reverse transcriptase; UL = upper limb; WHO = World Health Organization; frontal lobe; intraparenchymal; malignant intracerebral nerve sheath tumor; malignant peripheral nerve sheath tumor; malignant schwannoma.

Publication types

Case Reports