Longitudinal MR findings in a patient with hemimegalencephaly associated with tuberous sclerosis.

A patient with an unusual association between tuberous sclerosis complex and hemimegalencephaly is reported. At 2 days of age, CT scan disclosed right hemimegalencephaly with periventricular faint calcification. At 1 month of age, magnetic resonance imaging showed right hemimegalencephaly with T1 and T2 shortening. The right frontal and parietal lobes were compatible with transmantle dysplasia. At 6 months of age, the right hemisphere had decreased in size. Atrophic changes continued to progress until 3 years of age. Periventricular calcification in the right hemisphere became marked with age. The patient developed frequent partial motor seizures from 6 weeks of age and infantile spasms from 5 months of age. Electroencephalogram revealed low amplitude of background activities in the right frontal area. The cause of this atrophic change in the hemimegalencephalic hemisphere, which could be a hamartomatous lesion, remains unknown.