Posterior fossa malformations and epilepsy

The association between posterior fossa malformations and epilepsy is rarel y reported in the literature. We describe 54 cases with posterior fossa mal formations, according to embryogenesis classification, divided into two gro ups on the basis of presence or absence of epilepsy. Epilepsy occurred in 2 2 cases (40.7%) and was not related to the type of posterior fossa malforma tion or to supratentorial cerebral lesions associated with the malformation . Familial antecedents for epilepsy and/or febrile convulsions influenced t he presence of epilepsy in patients with posterior fossa malformations (P < .01). Epilepsy was mainly partial (77.3%); benign partial/generalized epil epsies and febrile convulsions occurred in 27.3% of cases. Seizures disappe ared for 2 or more years at the end of follow-up in 36.4% of patients. Good epilepsy prognosis was not related to the age at onset of seizures, famili al antecedents for epilepsy and/or febrile convulsions, supratentorial asso ciated lesions, or age of patients at the last observation. Profound mental retardation prevailed in patients with epilepsy (P < .01), as did patholog ic electroencephalograms (EEG) (P < .0001), with paroxysmal abnormalities ( P < .001) and asymmetry (P < .01). In our 54 cases of posterior fossa malfo rmation, we identified two risk factors for epilepsy: familial antecedents for epilepsy and/or febrile convulsions and the involvement of the cerebell um in the malformation.