The case of a 15-year-old right-handed girl with developmental delay, mild retardation, astereognosis, and tactile discrimination impairment in the left arm, is reported. During sleep, right partial simple motor seizures with sialorrhea and saliva pooling were present, sometimes followed by secondary generalization. Absences and drop attacks were also observed. Electroencephalography revealed left centrotemporal spike waves spreading to the homologous contralateral region, generalized 3-Hz spike-and-wave complexes enhanced by hyperventilation, and generalized polyspike-and-wave discharges during drowsiness. Magnetic resonance imaging showed right perisylvian (opercular) malformation. Benign epilepsy of childhood with centrotemporal spikes (BECCTS) is a focal idiopathic epilepsy presumed to be of genetic origin. Although brain damage is not expected, structural lesions including opercular macrogyria have been reported. This coexistence has been considered mainly causal and only exceptionally causal. The Foix-Chavany-Marie syndrome or operculum syndrome is the result of bilateral opercular damage. In our child the right structural and the left functional lesions appeared mutually activated, yielding a transient opercular syndrome. The concomitance of BECCTS and developmental opercular dysplasia is suggestive of a common genetic substratum.