Congenital Malformations

A 2.5-month-old female was admitted with a chief complaint of enlarged head on our clinic. CT scan showed abnormalities of the telencephalon with severe subdural effusion, and subdural-peritoneal shunt was performed for increased intracranial pressure. Thereafter, because of dysfunction of the shunt system, she was received four times of shunt revision. She died of the acute renal failure when she was 14-month-old. On CT scan, agenesis of the falx, deficient separation of the prosencephalon, and the dorsal sac were seen. Then, a diagnosis of semilobar holoprosencephaly was made from fmdings of CT scan and cerebral angiography. On post mortem examination, frontal portion of the lateral ventricle (mono-ventricle without having the septum-formation) communicated with two different directions. The one was the ordinary route which passed to the third ventricle, the aqueduct and the fourth ventricle. The other was a narrow duct of 1-2 mm in diameter and about 10 mm in length which passed posteriory and formed connection with the dorsal sac. The sac was also mono-ventricular with huge choroid plexuses and antero-lateral portion was transformed to tip of the temporal hom bilaterally. It was thought that the dorsal sac might be ruptured and resulted in retention of CSF in the subdural space observed in CT and angiography. In holoprosencephaly hitherto reported, such a case with malformations as this is extremely rare.