Monozygotic twins discordant for urinary tract anomalies and presenting as hydramnios

This report describes premature monozygotic twins, 1 of whom had an unusual clinical manifestation of a rare congenital anomaly, the other being normally developed. Hydramnios had been suspected during pregnancy and, because of the severity, amniocentesis was attempted. However, it became evident that the hugely distended abdomen did not indicate hydramnios, the pregnancy actually being complicated by oligohydramnios. Pulmonary hypoplasia was the cause of the immediate neonatal demise of 1 twin; the other expired after prolonged therapy for meconium aspiration. No similar cases have been reported in the literature which is reviewed briefly. Particular attention is given to discordant anomalies in monozygotic twins, the mode of their placentation, and the development of amnion nodosum.