Epilepsy and perisylvian lipoma/cortical dysplasia complex

Intracranial lipomas are congenital malformations composed of mature adipoc ytes. They are usually located in the midline, particularly in the pericall osal region, a hemispheric location accounting for only 3 to 7% of cases. R eview of the literature found 21 previous cases of hemispheric lipoma. Alth ough hemispheric cerebral lipomas are rare, association with epilepsy appea rs to be frequent. We have recently studied two patients in whom epilepsy was the first clinic al manifestation of hemispheric cerebral lipoma in the sylvian region. The patients presented with simple motor partial seizures as the first manifest ation of the lesion. Neurological examination was normal. MRI disclosed in both cases a lesion involving the sylvian fissure with characteristics of t he lipid signal. MRI also demonstrated abnormalities involving the cerebral cortex in the vicinity of the lesion (pachygyria-like aspect). Partial exc ision of the lesion was achieved in one patient but was followed by a worse ning of seizures and neurological condition (hemiparesis). According to the literature, the prognosis for epilepsy in patients with hemispheric lipoma appears good. Several other arguments support non-surgical management : th e lesion is benign and can be identified with a high degree of certainty by imaging; surgery is technically difficult due to adherence to adjacent vas cular and cerebral structures and hypervascularity; location near functiona l brain tissue increases the risk of postoperative sequelae. In addition, m echanisms of epilepsy probably involve vascular and cortical dysplasic abno rmalities. In consideration of the complexity of the lesion, hemispheric li pomas are more appropriately classified with localized cortical malformatio ns rather than as simple extracerebral malformations.