- Etiology: not clear, leading theory is abnormality in development of mesoderm early in gestation resulting in abundance of fibrous tissue with lack of musculature, lack of musculature affects abdominal wall / ureters / bladder / urethra to variable degree, abdominal musculature may also account for failure of testes to descend
— Classic triad: abdominal muscle hypoplasia, urinary tract dilation without obstruction presenting as flank masses, bilateral cryptoorchidism - Prenatal US: protuberant abdomen, severe urinary tract dilation, variable degree of pulmonary hypoplasia, variable degree of oligohydramnios
- Radiograph: bulging flanks, variable degree of pulmonary hypoplasia
- US: large bladder which may be thick walled when empty, dilated ureters (distal >> proximal), atrophic / dysplastic kidneys from vesicoureteral reflux
- VCUG: capacious urinary bladder that is not hypertrabeculated, markedly dilated and tortuous ureters, patent urachus may be present, megalourethra frequently seen (especially prostatic urethra), vesicoureteral reflux in 85% of cases, impaired clearance from ureters
- Clinical: almost exclusively in males