Prenatal diagnosis of cloacal exstrophy before rupture of the cloacal membrane

Cloacal anomalies exhibit a wide variety of morphologic types and accompanying clinical severity. The association of malformations of the cloaca with partial, complete, or conjoined twinning has been appreciated for some time, but, with the advent of prenatal ultrasound technology, appears to occur with a greater frequency than once thought. This observation has important implications for pathogenesis. We present 2 representative cases, a 19-week-old female fetus with duplication of several caudal structures and a 21-week-old male fetus with cloacal exstrophy variant and demised co-twin with lower abdominal wall defect, extruded intestinal tract, absent external genitalia, and imperforate anus. These findings and previously published theories suggest that certain models of monozygotic twinning may apply to the pathogenesis of cloacal anomalies. Specifically, the partial or complete duplication of the organizing center within a single embryonic disc may increase the risk of mesodermal insufficiency and thus account for the failure of complete development of the cloacal membrane and consequent exstrophy or other aberration.

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Common (“Classical”) and Covered Cloacal Exstrophy: A Histopathological Study and a Reconstruction of the Pathogenesis

Pediatric and Developmental Pathology ◽

10.2350/07-06-0292.1 ◽

2008 ◽

Vol 11 (6) ◽

pp. 430-442 ◽

Cited By ~ 7

Author(s):

S.C.J. van der Putte ◽

W.G.M. Spliet ◽

P.G.J. Nikkels

Keyword(s):

Normal Development ◽

Primitive Streak ◽

Histopathological Study ◽

Current Idea ◽

Extraembryonic Tissue ◽

Cloacal Exstrophy ◽

Current Opinion ◽

Cloacal Membrane ◽

Blind Ending ◽

Autopsy Specimens

Current opinion about structure and pathogenesis of cloacal exstrophy was challenged by histopathological findings and new insights into the normal development. Autopsy specimens of common ( n = 3) and covered cloacal exstrophy ( n = 4) with single intraexstrophic and -perineal phallic structures and perineo-exstrophic canals have been analyzed histopathologically. The findings were correlated to normal development to reconstruct the pathogenesis. By identifying a specific cloaca-derived urethra field as distinct from allantois-derived bladder fields, the exstrophic area is found to reflect the original hindgut configuration in embryos of approximately 26–29 postovulatory days gestational age (2–4 mm). Correlation to normal development suggests malfunctioning of the primitive streak/caudal eminence as a primary fault that leads to a defective cloacal region in the hindgut disturbing cloacal-intestinal-allantoic dissociation and also causes lengthening of the intestinal region into a blind-ending colon, teratoma-like lesions, and vertebral and muscular anomalies. The current idea that membranes in “covered cloacal exstrophy” represent persisting cloacal membranes is dismissed by finding an amnion-like structure, which suggests dysfunction of an umbilical ring placode as a simultaneous 2nd fault. This malfunctioning may cause omphalocele by defective demarcation of the umbilical cord and may replace midline stroma of the infraumbilical abdominal wall by extraembryonic tissue that stretches into a weak temporary membrane, may leave a perineo-extrophic canal, and may allow the formation of a single perineal or intraexstrophic phallus. Malfunctioning without replacement may result in a purely epithelial “allantoic” membrane, which by disintegrating in combination with the cloacal membrane will expose common cloacal exstrophy.

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