CHALLENGING THE EMBRYOGENESIS OF CLOACAL EXSTROPHY

As presently understood, cloacal exstrophy results from a migration fa ilure of the lateral mesodermal folds of the infraumbilical anterior a bdominal wall, and rupture of the resulting enlarged, persistent cloac al membrane before the eighth week of gestation. The authors present u ltrasonographic evidence that disputes this embryological theory. Rout ine ultrasonography of a twin gestation at 18 weeks showed that one tw in had a dilated cloacal abnormality, bilateral hydronephrosis, and ol igohydramnios. Repeat ultrasonography at 24 weeks demonstrated rupture of the cloacal anomaly, with resolution of both the hydronephrosis an d oligohydramnios. This twin was born with classic cloacal exstrophy. This striking ultrasound evidence of an intact cloacal membrane at 18 weeks, which ruptured before 24 weeks, relieving the urinary tract out let obstruction, forces us to rethink how this surgically correctable anomaly develops. Copyright (C) 1996 by W.B. Saunders Company