Various hippocampal malformations have been described in the context of widespread cortical malformations inpatients with epilepsy. Isolated hippocampal malformations however are very rarely identified on MR imaging studies. Little is known about the epileptogenicity of these malformations and their pathologic appearance. We present a case with severe bilateral hippocampal malformations who underwent right temporal lobectomy due to intractable temporal lobe epilepsy. Postoperative examination of the resected hippocampus revealed abnormal shape of the dentate gyrus and an atypical convolution of the CA1 pyramidal cell-subicular layers. After surgery, the patient has been seizure free. (c) 2009 Elsevier B.V. All rights reserved.