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  • Updated 03.14.2023
  • Released 09.12.1994
  • Expires For CME 03.14.2026

Colpocephaly

Introduction

Overview

Colpocephaly refers to the selective dilatation of the occipital horns with normal or small frontal horns and 3rd ventricle. It is often confused with hydrocephalus. It is commonly described as hydrocephalus or ventriculomegaly. The distinction is important because hydrocephalus usually requires shunting, affects all the ventricular system, and is often progressive and obstructive, whereas colpocephaly is an occipital selective, nonprogressive, and nonobstructive condition that does not require surgical treatment. Colpocephaly can occur isolated or associated with diverse anomalies and genetic syndromes.

Key points

• Colpocephaly is the selective dilatation of the occipital horns of the lateral ventricles. It is the most frequent anomaly of the ventricular system after hydrocephalus.

• Colpocephaly is often confused with hydrocephalus, but intraventricular pressure is not increased.

• The most frequent association is with agenesis or dysgenesis of the corpus callosum with diminished white matter in the posterior half of the telencephalon.

• There are many associated genetic syndromes and also many other associated brain malformations

• Diagnosis can be made by any modality of neuroimaging: cranial ultrasound, CT, or MRI, including prenatally.

• Shunting is rarely required.

Historical note and terminology

In 1940 Benda first recognized the "failure of decrease in the size of the primitive brain vesicles" in a mentally retarded boy with epilepsy and microcephaly who, on neuropathological examination, also had an absent corpus callosum, micro- and macrogyria, and gray matter heterotopia. He used the term "vesiculocephaly" for this ventricular configuration (12). In 1946 Yakovlev and Wadsworth discussed this same patient as a case of fused lip schizencephaly and suggested the term colpocephaly instead (from the Greek "kolpos," meaning hollow) to "avoid the miscegenation of the Latin and Greek roots" (106). Initially, colpocephaly referred to persistent global wide ventricles (07). Later, the term "colpocephaly" was restricted to the persistence of a specific form of fetal ventricular configuration into postnatal life where occipital horns of the cerebral ventricles remain disproportionately large and dilated (42). This term found wide acceptance and has been used since. The colpocephalic configuration of the ventricles is presently most easily recognized by computed tomography or magnetic resonance imaging of the brain.

Colpocephaly in a 6-week-old boy (CT)
Note the dilated occipital horns of the ventricles with reduced periventricular white matter. There also is absence of the corpus callosum with wide separation of the frontal horns. (Contributed by Dr. Bhuwan Garg.)

In the past, pneumoencephalography or ventriculography was used for the same purpose (42).

Colpocephaly is often confused with hydrocephalus, both in the fetus (06) and also at later postnatal ages. It is commonly described as hydrocephalus or ventriculomegaly. However, they are different anomalies and should be distinguished. Colpocephaly refers to the selective dilatation of the occipital horns with normal or small frontal horns and 3rd ventricle. The distinction is important because hydrocephalus usually requires shunting, affects all the ventricular system, and often is progressive and obstructive, whereas colpocephaly is an occipital selective, nonprogressive, and nonobstructive condition that does not require surgical treatment. An exception exists when colpocephaly coincides with obstructive hydrocephalus (75). Fetal ventriculomegaly refers to enlarged cerebral lateral ventricles in the fetus with a transverse diameter of the atrium above 10 mm by ultrasound (20).

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