Epigastric heteropagus conjoined twins: two case studies and associated DNA analysis

Conjoined twins are rarely observed, but heteropagus conjoined twins occur even less frequently. Heteropagus conjoined twins are asymmetrically conjoined twins, in which one twin is nearly anatomically normal (autosite), and the other twin remains anatomically incomplete (parasite) but physically attached to the autosite. Epigastric heteropagus conjoined twins (EHTs), referring to a parasitic twin who is attached to the epigastrium of the autosite, are extremely rare (1). Due to the rare incidence of EHTs, there are few publications on this subject, which has resulted in a general lack of knowledge among surgeons with respect to how to approach the management of EHTs. Furthermore, EHTs generally manifest as more medically complex situations than typical conjoined twins. Therefore, the etiology, manifestation, and therapeutic outcomes of EHTs remain controversial. In this article, we report two cases of EHTs encountered in our department between May 2007 and October 2007. One EHT case involved a large ventral hernia near the omphalocele, which has not been previously reported. Moreover, DNA analysis of case number 2 suggested a monozygotic origin of the EHTs.