KEY FACTS
Terminology
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Disorder characterized by 3 principle components
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Dramatic collecting system dilatation
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Deficiency of abdominal musculature
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Cryptorchidism (undescended testes)
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Imaging
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Gross dilatation of bladder, ureters, and renal pelves
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Urethral dilation without obvious point of obstruction
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Scan genitalia: Look for undescended testes
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Oligohydramnios often present
Clinical Issues
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Almost all cases are male fetuses
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Prognosis dependent on severity of oligohydramnios (results in pulmonary hypoplasia) and renal damage
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Postnatal flaccid, “doughy” abdomen from lack of musculature
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~ 1/2 of patients surviving infancy will develop chronic renal disease
Scanning Tips
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Difficult to differentiate from posterior urethral valves (PUV); look for following differentiators
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Prune-belly syndrome (PBS) does not have dilated posterior urethra
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No keyhole sign as seen with PUV
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Entire urethra may be dilated
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Ureters and kidneys always dilated with PBS
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May be normal with PUV
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Bladder wall is thin with PBS
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Often thickened and trabeculated with PUV
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May be difficult to see when bladder is dilated but pay particular attention if bladder is tapped
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Scan genitalia looking for undescended testes
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Important feature of PBS
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, extending well into the abdomen with adjacent hydroureter 
. Note the absence of a keyhole sign, which is usually seen with posterior urethral valves.
with a lack of the typical echogenic oval testes. The median raphe of the scrotum 
is noted.
