We report the case of a 21-year-old man who presented drug-resistant epilepsy since the age of 3 years. The underlying type Ia left prefrontal focal cortical dysplasia was revealed by focal hypermetabolism of FDG-PET several years later. The stereo-electroencephalography showed continuous interictal rhythmic spike discharges, suggesting the dysplastic character of the cortex explored by depth electrodes placed into and at the margins of PET abnormalities. The surgical limits of resection were defined based on interictal activity, spontaneous and induced seizures. The patient is seizure-free, with normal electroencephalography and clear improvement of neuropsychological performance, without functional deficit at 3 years postsurgery.