Prenatal sonographic diagnosis of a twinning epigastric heteropagus.

Epigastric heteropagus is a rare type of conjoined twinning which results from an ischemic atrophy of one fetus at an early stage of gestation. We present what we believe to be the first case diagnosed antenatally at 22 weeks' gestation. The pelvis and lower limbs of the ischemic fetus (the parasite) were attached to the epigastrium of the well-developed fetus (the autosite), which had a small omphalocele. Antenatal sonography provided an accurate diagnosis, enabling unnecessary abortion to be avoided.