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Cloacal exstrophy: prenatal diagnosis before rupture of the cloacal membrane
J C Langer1, B Brennan, R E Lappalainen
1Department of Surgery, McMaster University, Hamilton, Ontario.
Insights
Cloacal exstrophy, a rare congenital anomaly, was diagnosed prenatally via ultrasound. This case challenges current embryological understanding, suggesting a later rupture of the cloacal membrane.
Area of Science:
- Developmental Biology
- Medical Imaging
- Obstetrics
Background:
- Cloacal exstrophy (CE) is a complex congenital anomaly.
- Embryologically, it's linked to infraumbilical cloacal membrane rupture around the fifth embryonic week.
Observation:
- Prenatal ultrasound identified monoamniotic twins at 17 weeks gestation.
- One twin exhibited sacral myelomeningocele, abnormal feet, splayed pubic rami, and an abdominal cystic mass.
- Subsequent ultrasounds showed cyst resolution, omphalocele, absent bladder, and possible bowel prolapse.
Findings:
- Postnatal examination confirmed cloacal exstrophy, myelomeningocele, limb anomalies, and foreshortened small bowel.
- The observed cloacal membrane rupture after 22 weeks contradicts established embryological timelines.
- Prenatal ultrasound demonstrated characteristic features of cloacal exstrophy.
Implications:
- This case necessitates re-evaluating the embryogenesis of cloacal exstrophy.
- Early and accurate prenatal diagnosis via ultrasound is crucial.
- Enables informed prenatal counseling and optimized perinatal management strategies.
Abstract:
Embryologically, cloacal exstrophy is thought to result from persistence and subsequent rupture of the infraumbilical cloacal membrane during the fifth embryonic week. We report a case of cloacal exstrophy in which a prenatal diagnosis was made prior to rupture of the cloacal membrane. A routine ultrasound at 17 weeks' gestation demonstrated monoamniotic twins. One twin was normal, but the other was found to have a sacral myelomeningocele, "rocker-bottom" feet, splaying of the pubic rami, and a large cystic mass protruding from the infraumbilical anterior abdominal wall. A repeat ultrasound was performed at 22 weeks, with the same findings. At 26 weeks, further examination showed disappearance of the abdominal cyst, a small omphalocele, no demonstrable bladder, and the suggestion of prolapsed bowel inferior to the umbilical cord insertion. After delivery at 34 weeks, the abnormal twin was found to have the typical findings of cloacal exstrophy, myelomeningocele, bilateral lower limb anomalies, and extremely foreshortened small bowel. Rupture of the presumed cloacal membrane after 22 weeks in this case is inconsistent with our current understanding of the embryology of this anomaly, and should stimulate a reexamination of the current concepts. If the characteristic features are recognized, cloacal exstrophy can be diagnosed by prenatal ultrasound, permitting prenatal counseling and appropriate perinatal management.