A 41-year-old man had a right frontal grade I glioma resection 17 years ago. He was tumor free since. However, 1 month ago, he presented with an uncontrollable seizure, which raised the possibility of recurrent tumor. The 18FDG PET/CT brain scan showed increased tracer uptake at the margin of the previous resected tumor, suggesting the possibility of tumor recurrence. However, on a repeat FDG PET brain scan confirmed by electroencephalography monitory as an interictal study, no elevated FDG uptake was revealed at this site. These results indicate that the elevated 18F-FDG activity on the original study was a result of seizure.