[Cerebral lesions observed in a twin after the in utero death of the other twin. Fetal anoxia-ischemia can be the possible mechanism (3 cases)].

BACKGROUND

The death of one twin in utero may result in visceral lesions, of possible vascular origin, in the surviving twin when the pregnancy is monochorionic and diamniotic.

CASES REPORT

Case n. 1: The death of one twin and enlargement of the ventricular system in the other were seen by ultrasonography at 24 weeks of pregnancy, 8 weeks after the mother had a fall on the stairs. The heterogeneous imaging in the inferior part of placenta suggested a clot in this area. The pregnancy was terminated at 28 weeks because the ventricular dilatation continued to increase. The newborn died a few minutes later and examination of the placenta showed that the pregnancy was monochorionic and monoamniotic. Case n. 2: The death of one twin with macerating features was seen by ultrasonography at 31 weeks. The other twin was born at 32 weeks of a dichorionic, diamniotic pregnancy. Injection of milk into the placental vasculature failed to visualize any vascular anastomoses between the two placentas, but ultrasonography showed bilateral cystic lesions in the frontal lobes of the brain. Case n. 3: Acute polyhydramnios developed at 21 weeks of pregnancy; it was treated by 3 amniocenteses, while ultrasonography of the twins was normal. A fetal transfusion syndrome was observed at birth, the pregnancy being monochorionic and diamniotic. Cranial ultrasound on day 6 was normal in the recipient twin, but showed numerous cerebral cavities in the donor, which was confirmed at autopsy after that this twin suddenly died at 2 months of age.

CONCLUSIONS

Brain lesions of vascular origin, can be observed in any type of twin pregnancies. They may be the result of transfusion of clot or thromboplastin-rich blood from the donor fetus through vascular anastomoses in a monochorionic placenta. They also may be due to anoxo-ischemic lesions in the absence of such anastomoses, or, in the fetal transfusion syndrome, to circulatory difficulties in one of the twins, as observed in premature singletons. In the cas of anoxo-ischemic lesions, anticipating the birth of the surviving twin is not justified.