The presence of metabolic abnormalities on [18F]FDG PET images in patients with recurring seizures after brain surgery for epilepsy is poorly investigated. The pattern of hypometabolism surrounding the surgical cavity could be partly explained by disconnection phenomena and the value of [18F]FDG PET in this indication is poorly investigated in the literature. We report here a case in which the residual mesial temporal structures were severely hypometabolic, concordant with electro-clinical information pointing toward right temporal medial epileptogenic zone. The severe hypometabolic pattern, together with a deficit in non-verbal memory, was in favor of a severe dysfunction of these structures and suggested a low risk of cognitive deficit after their resection. Resection of these structures resulted in seizure control and an improvement in non-verbal memory, suggesting that PET imaging, interpreted in combination with clinical, electrophysiological and imaging data, could provide useful information also in previously operated individuals.