Dual PET Imaging of an H3K27M-Mutant Glioma With 18F-GE-180 and 18F-FET PET

Abstract A 25-year-old man presented with headache and intracranial pressure symptoms. On MRI, an intracranial lesion was detected in the right thalamus with exophytic growth into the third ventricle and inhomogeneous contrast enhancement without necrosis. Dual amino acid ( 18 F-FET) and TSPO ( 18 F-GE-180) PET imaging showed high tumor-to-background ratios in both scans and a short time-to-peak in 18 F-FET uptake dynamics. Biopsy revealed a diffuse midline glioma, H3K27M-mutant (WHO grade IV), a novel entity in the 2016 WHO classification with poor clinical outcome. Our case shows that the highly aggressive features of this tumor entity can be visualized in vivo by both PET modalities.