Anatomical-clinical correlations and EEG findings in 10 children, aged 26 months to 11 years (median 6 years), with drug resistant partial epilepsy and focal cortical dysplasia, operated on 1996-2000, were analysed at the Epilepsy Surgery Centre “C Munari” in Milan, Italy. MRI abnormalities were unilobar in 5, bilobar in 2, and multilobar in 1. Two with negative MRIs had frontal lobe seizures. Surgery consisted of corticectomy plus lesionectomy in all cases. Seizures were completely controlled at 25 month follow-up or longer in 70% patients. Outcome was poor in multilobar patients. Development improved after surgery in all patients. Stereo EEG exploration in the most complex cases helped to define the epileptogenic zone in frontal, extratemporal and multilobar epilepsies. Stereo EEG facilitated resection of extralesional cortex. 
COMMENT. Seizures are controlled following surgery in 70% of children with drug-resistant partial epilepsies and histologically confirmed focal cortical dysplasia. Stereo invasive EEG recording delineates the epileptogenic zone in patients with extratemporal epilepsies, and especially those with negative MRI.