A 12 year-old girl presented for evaluation of poor school performance, and spells suggestive of complex partial seizures.

Heterotopic gray matter is a developmental malformation wherein some neurons do not migrate to their expected location, instead forming clumps of gray matter, usually in the deep cerebral white matter or lining the walls of the lateral ventricles (periventricular nodular heterotopia). This condition is on the spectrum of neuronal migration disorders. Neurological sequelae may include seizures, mental retardation, learning disabilities and impaired fine coordination.