Revealing subependymal giant cell astrocytoma with multimodal positron emission tomography: illustrative cases

BACKGROUND There is limited literature on the use of positron emission tomography (PET) for benign tumors originating in the brain ventricles, and the use of multiple tracers for subependymal giant cell astrocytoma (SEGA) has not been reported. The authors compared the PET findings in two SEGA cases with past reports and literature, exploring the distinctive characteristics of SEGA on PET. OBSERVATIONS In a 21-year-old female with SEGA, the authors utilized 18F-fluorodeoxyglucose (18F-FDG), 11C-methionine (11C-MET), 18F-fluorothymidine (18F-FLT), 18F-fluoromisonidazole, and 18F-THK5351 tracers. Additionally, in a 6-year-old girl, the authors performed 11C-MET PET. LESSONS The results indicated the accumulation of all tracers except 18F-FDG, with particularly intense accumulation noted with 18F-FLT. In particular, 18F-FLT demonstrated accumulation comparable to that observed in malignant tumors. This study suggests that multiple PET tracers can provide valuable insights into the characterization of SEGA, with 18F-FLT showing particular promise as a distinctive marker of blood-brain barrier disruption. Further research in larger cohorts may enhance our understanding of metabolic patterns in SEGA and aid in its diagnosis and treatment.