We report the case of a child with isolated late-onset epileptic spasms who significantly improved after focal frontal cortectomy. Clusters of axial and limb tonic contractions with head nodding began at 2 years of age. They occurred only during sleep, lasting 15 to 20 minutes and were pharmacoresistant. The child suffered slight mental delay. Interictal EEG showed left frontal spikes in slow sleep. Ictal video-EEG showed patterns of asymmetric spasms. MRI revealed a distinct white matter abnormality in the left frontal superior gyrus, corresponding clearly to localised cortical hypometabolism on FDG-PET and PET-MRI co-recording. SEEG investigation showed that the first spasm of the clusters corresponded to a localised discharge of rapid rhythms from the electrodes placed within the area identified as a lesion by MRI. Discharges then became more diffuse across the left frontal and temporal electrodes throughout the duration of the cluster. A tailored focal frontal resection was performed at 16 years of age. Spasms were very rare during the following three years (Engel class II). This observation illustrates the fact that isolated epileptic spasms can be cured by focal cortical resection despite a lack of clearly localised EEG surface anomalies.