Limb-body wall complex: 4 new cases illustrating the importance of examining placenta and umbilical cord

Limb-body wall complex (LBWC) is a rare, sporadic, congenital defect define d as a combination of at least two of three characteristics: 1. limb defect s, 2. anterior body wall defects, and 3. exencephaly or encephalocoele with /without facial clefts. Three pathogenic mechanisms have been proposed: ear ly amnion rupture, vascular disruption and embryonic dysgenesis. In this st udy we carried out the pathological evaluation of four fetuses with LBWC an d their placentas. None of the cases had craniofacial defects. Three fetuse s showed an abdominal wall defect with eventration of abdominal organs, clo acal exstrophy, absent external genitalia, abnormal internal genitalia, sco liosis and lower limb defects. One fetus showed failure of closure of both thoracic and abdominal walls with ectopia cordis, evisceration of left lung and abdominal organs, severe reduction defect of left arm, but normal colo n, anus, bladder, genitalia and lower limbs. All cases had a short, malform ed umbilical cord, incompletely covered by amnion. The umbilical vessels we re embedded in an amniotic sheet which connected the skin margin of the ant erior body wall defect to the placenta. These anomalies suggest an abnormal body stalk development as a pathogenic mechanism for LBWC. Prenatally, the abnormal fetoplacental attachment can be detected ultrasonographically by the end of the first gestational trimester. Postnatally, the examination of placenta, umbilical cord and membranes is crucial in confirming the diagno sis of LBWC.