Radiological MRI-negative temporal lobe epilepsy (TLE) is a common, but challenging subtype for surgical treatment. Compared to MRI-positive cases, these patients often require invasive EEG for localization that may also involve extratemporal regions. Furthermore, these cases entail a lower likelihood of seizure-free surgical outcome. To better understand this important group, we studied cortical surface features of MRI and FDG-PET to relate occult extratemporal damage to epilepsy localization and surgical outcome prediction. Bilateral cortical morphological changes were found. FDG-PET hypometabolism was lateralized in the hemisphere ipsilateral to seizure focus. Extratemporal and bilateral hypometabolism tended to be associated with poor surgical outcome.