Craniofacial Duplication (Diprosopus) in the Cat — Case Report and Review of the Literature

A kitten displaying the features of symmetrical partial duplication of the head (diprosopus) is described. The morphological description of this double monster is compared to three previous similar cases. All four cases were similar in that duplication of the orbits and eyes were not completed and fission of the oral and nasal cavities and their contents were partial. Furthermore, the central nervous systems were duplicated as far caudal as the brain stem. Present case displayed cleft palate in the two faces, a feature that was not described earlier. Though diprosopus is a rare anomaly in cats, it is more common than in the dog, pig and sheep. In cattle, anterior duplications are one of the largest groups of congenital anomalies. Based on generally accepted considerations concerning the mechanism behind the formation of monozyous twins, conjoined twins and anterior duplications, integrated with experimental data on induction of duplications in animals, an hypothesis is proposed for early embryonic fission. It suggests a constant cleaving factor active along the median plane with affinity to midline structures. Its temporal relations with the developing embryo, especially in susceptible species, decide the degree and type of duplication