Lumbosacral parasitic rachipagus twin.

A rare case of a newborn girl presenting with a mass representing an aborted parasitic twin attached to the back in the midline over the lumbosacral region (parasitic rachipagus) is reported. Rudimentary digits were attached to the mass, and in one area, the overlying skin resembled scrotal skin. A depression resembling an anal dimple was also present on the surface of the mass. Investigations showed a well-developed long bone and other small bones within the parasite, and sacral spina bifida in the autosite. Successful surgical excision of the parasitic mass was performed. A review of the literature pertaining to parasitic rachipagus twinning is presented.