• The temporal lobe agenesis syndrome is a rare congenital abnormality. In previous case reports, this syndrome has been described in association with arachnoid cysts or abnormal collections of CSF. An autopsy performed in the case of our 25-year-old patient revealed agenesis of frontal and temporal lobes without an anatomic cyst. During life the patient had no neurologic abnormalities that could be related to the lesion.