A healthy child with history of encephalitis 4 years ago now describes progressive right side weakness and intractable seizures. The CT findings, history and clinical presentation fit the criteria of Dyke-Davidoff-Masson syndrome.

The etiology of the syndrome is abnormal insult that happens either intrauterine or early in life results in hypoplasia/atrophy of a cerebral hemisphere. The main differential of the syndrome is Rasmussen encephalitis which isn't characterized by hypertrophied skull and Sturge-Weber syndrome which was excluded by the normal pre insult imaging findings.