Antenatal diagnosis of complete facial duplication--a case report of a rare craniofacial defect.

We report a case of the prenatal sonographic detection of facial duplication, the diprosopus abnormality, in a twin pregnancy. The characteristic sonographic features of the condition include duplication of eyes, mouth, nose and both mid- and anterior intracranial structures. A heart-shaped abnormality of the cranial vault should prompt more detailed examination for other supportive features of this rare condition.