Craniofacial duplication: one of the rarest malformations in humans

Craniofacial duplication is a twin pregnancy defect; particularly in monozygotic, monochorionic and monoamniotic pregnancies. Of all twin pregnancy complications, the least frequent is a fetus with craniofacial duplication (dipro- sopus). In this article we report a case with this condition, and we review the literature on this rarest of human malformations.