A case of iliothoracopagus (dicephalus tribea chius tripus) with a consideration of the “budding” and “fission” theories of twinning

Abstract

The case to be presented is that of conjoined, female infants who were born prematurely at the end of the seventh lunar month, who died soon after birth and whose combined weight after preservation in formalin was 2016 , g m . (fig. I).' This form of equal but incomplete twinning should be classified as Perpendicular Symmetrical Duplication (dicephalus tribrachius tripus) or as Supra-and Infra-umbilical Ventro-lateral Union (iliothoracopagus) ; see Fisher (1866), Schwalbe ( '07), Kubner ( '11) and Scammon ( '24). Although there are at least twelve similar cases in the literature, only one of them has been studied by means of adequate dissection, namely Rover's case ( '37).2 I n order to facilitate description and discussion, the right twin (the one on the left in fig. 1) will be referred to as Twin I and the left as Twin 11. Likewise certain structures and their embryonic primordia will be designated either I or 11.' The specimen was received from Dr. E. G. Oppen, Minneapolis, who kindly supplied the following clinical information. The mother was a primipara, aged 24, and her Wasserman test was negative. Because of placenta previa, vaginal bleeding occurred before hospitalization. I n spite of progesterone a d sedatives. premature delivery wau spontaneous. The menstrual age of the twins was 197 days. Insofar as the mother could recall the first month of her pregnancy, there were ~ieither abnormal symptoms nor complicating events.Rover's ease differs from ours by exhibiting such anomalies as horseghoe kidney, absence of one umbilical artery, presence of two superior venae cavae in the left twin and passage of the left subclavian artery behind the esophagus i n the right twin. Also, his case fails t o show an anomalous right subclavian artery i n the left twin. The other eleven cases are as follows. Eight are those collected from the literature by Rover; of them, it was possible t o review five, namely those of Agaronian ('34). Batnew (case 1, 'OO), Kasprzak ('10) and Sehwalbe (two cases, '07). I n addition to the cases listed by Rijver, there are those of Benedini (1844). Reaves ( '39) and Wynian (1866).