Colpocephaly: frequency and associated findings.

Colpocephaly is an abnormal enlargement of the occipital horn of the lateral ventricle, also described as persistence of the fetal configuration of the lateral ventricles. Since it was first described, colpocephaly has been found in association with a number of abnormalities of the brain. In order to determine the frequency of this ventricular configuration at our hospital, we reviewed 3,411 computed tomographic (CT) scans done over a 26-month period. Fourteen cases were identified in which the CT scan had the appearance of colpocephaly. These CT scans were performed during the evaluation of a number of different clinical problems. Agenesis of the corpus callosum was the most frequently associated malformation. The types of malformations commonly associated with colpocephaly suggest that colpocephaly is merely a marker of disordered brain formation and that insults occurring anytime between one and four months of gestation may result in this anomaly.