Abstract
Background: The simultaneous occurrence of low-grade and high-grade gliomas in different brain regions of the same patient is exceedingly rare. This phenomenon may represent malignant progression of a pre-existing low-grade glioma, true synchronous gliomas, or multicentric gliomagenesis. Distinguishing among these entities has important diagnostic, prognostic, and therapeutic implications.
Case Description: A 53-year-old man with no significant neurological history had been followed for several years for a stable left thalamic lesion radiologically suggestive of a low-grade glioma. He presented with acute visual impairment and was diagnosed with a left occipital hemorrhagic lesion. Subsequent magnetic resonance imaging revealed a contrast-enhancing occipital mass with radiological characteristics suggestive of a high-grade glial neoplasm, while the thalamic lesion remained unchanged. Perfusion imaging demonstrated increased vascularity within the occipital lesion. The patient underwent gross total resection of the occipital tumour, and histopathological examination confirmed a high-grade glial neoplasm. Given the long-term radiological stability and deep location of the thalamic lesion, no surgical intervention was performed.
Conclusions: The synchronous coexistence of low-grade and high-grade gliomas in distinct cerebral locations is exceptionally uncommon. This case highlights the diagnostic challenges associated with multiple gliomas and emphasises the importance of integrating clinical, radiological, histopathological, and molecular findings to differentiate malignant progression from truly synchronous tumours. Further molecular characterisation is essential to improve our understanding of glioma pathogenesis and multicentric tumour development.
