High-grade gliomas associated with neurofibromatosis type 1: analysis of imaging features and literature review.

Introduction: Neurofibromatosis type 1 (NF-1) is an autosomal dominant genetic disorder notably linked to the development of central nervous system neoplasms - predominantly low-grade glial tumours like pilocytic astrocytoma. High-grade glial neoplasms (HGG) are rarer and more prevalent in adults, with very few comprehensive studies on imaging features of the same. This study aims to investigate the imaging characteristics of HGG in patients with NF-1, to identify alarming imaging features that potentially indicate higher-grade tumours. Material and methods: Conducting a retrospective analysis, we examined histologically confirmed cases of HGG within clinically diagnosed NF-1 patients over 8 years. Our analysis scrutinised various imaging parameters, and histopathological and molecular data. Results: Eight cases of NF-1-associated HGG were identified. Predominant features included large tumour size (> 5 cm) in most (77.8%), intra-tumoral necrosis (77.8%), and moderate to marked perilesional oedema (55.55%). Notably, more than half were centred in midline structures. Molecular analysis highlighted diverse statuses of ATRX, IDH1R132H, and P53. Conclusions: This retrospective analysis of the largest single-centre dataset on imaging of HGG in NF-1 patients reported in the literature underscores that it may be more common than previously surmised. The need to look for alarming imaging indicators and raise suspicion in atypical locations like midline structures is essential for early detection and appropriate treatment.