Incidental Detection of Remote Ictal Hypermetabolism on FDG PET/CT Following Brain Metastatectomy: A Rare Diagnostic Pitfall.

FDG PET/CT is widely used in oncology but may occasionally show non-neoplastic hypermetabolic processes. We report incidental detection of probable ictal/peri-ictal hypermetabolism on follow-up FDG PET/CT in a 39-year-old woman with treated breast carcinoma and prior left temporal metastatectomy. Imaging demonstrated a postoperative cavity in the left temporal lobe and a focal intensely FDG-avid cortical area in the left posterior parietal region without CT correlate or other evidence of active systemic disease. The imaging pattern favored seizure-related cortical hypermetabolism rather than tumor recurrence. Recognition of this uncommon pitfall is important to avoid false-positive interpretation and inappropriate upstaging.