Dicephalus dipus dibrachius: an unusual case of conjoined twins.

Conjoined twinning is a rare anomaly, occurring in one of every 50,000 births. Dicephalus dipus dibrachius is an extremely rare form of conjoined twinning in which the infant has two arms, two legs, one trunk, but two heads. These infants are often stillborn or die shortly after birth. The authors describe a case of dicephalus twinning with 11-day survival. A thorough investigation using multiple imaging modalities (plain radiographs, contrast studies, ultrasonography, and magnetic resonance imaging) demonstrated that these twins had separate spinal columns but shared multiple internal organs including heart, liver, pancreas, intestine and bladder. Based on the anatomy of this case, the authors conclude that separation of dicephalus dipus dibrachius twins should not be attempted.