Abstract

Hemimegalencephaly is an uncommon sporadic congenital malformation of the central nervous system characterized by enlargement of one cerebral hemisphere with cranial asymmetry, hemiparesis, epilepsy, and mental retardation. This report deals with a 12-month-old girl with intractable seizure and developmental delay, who revealed hemispheric asymmetry and enlarged right cerebral hemisphere. MRI scan revealed asymmetric enlargement of right cerebral hemisphere with lissencephaly and multifocal calcification. She underwent right frontal lobectomy and parietal cortical resection, but died of complication of surgery. Histological features included loss of cortical lamination, large atypical neurons, neuronal heterotopia, and astrocytosis with dystrophic calcification. The heterotopic neurons in the white matter were suggestive of aberrant neuronal migration.

• Keywords: Hemimegalencephaly;Neuronal heterotopia;Micropolygyria;