[Anatomic study of a omphalosite monster].

The authors report the main anatomical features of a twin holoacardius amorphus monster. Diagnosis of the abnormality was assured by echography at the end of a "normal" gemellary pregnancy. Echograms were consistent with the diagnosis of "amorphus monster" and this was supported by dissection. The caudal extremity of the fetus was clearly identified by the presence of recognizable lower limbs in spite of the several abnormalities of the pelvic area. The cephalic extremity was characteristic of the malformation. Examinations of visceres allowed to precisely identify digestive structures such as intestinal loops (with disseminated atresias). It could not be find any kidney structure. Medially, a small rounded mass was observed and could be identified as hypoplasic cardiac structure. Other main anatomic features consisted of an enormous liquid-filled cavity largely communicating with both the lower part of the neural tube and the basis of the cranium. The placenta was unique and two umbilical with several and large anastomotic by-passes were increased from it.