BLADDER EXSTROPHY

• Rare malformation occurring in 1:25,000-40,000 births (1).
• Usually sporadic with a male to female ratio of 2:1 (1).
• Pathogenesis.

ULTRASOUND

• Ventral defect in the infraumbilical abdominal wall.
• Absent fetal bladder in its normal position within the pelvis (2).
• Normal kidneys.
• Normal amniotic fluid volume.
• The urinary bladder is exposed and opens anteriorly (the mucosal surface of the bladder is everted through the abdominal defect, with the bladder margins continuous with the abdominal wall resulting in a mucocutaneous junction) (3).
• Size of the exstrophied bladder is variable.
• Widening of the symphysis pubis (the degree of separation is proportional to the severity of the epispadias-exstrophy malformation) (4).
• Umbilicus is low set (caudal insertion) and may be involved in the area of extrophy.
• In males there is complete epispadias.
• In females the corresponding findings are bifid clitoris and wide labial separation.

REFERENCES

1. Engel RME. Exstrophy of the bladder and associated anomalies. Birth Defects 1974;10:146.
2. Barth RA, Filly RA, Sondheimer FK. Prenatal sonographic findings in bladder exstrophy. J Ultrasound Med 1990;9:359-361.
3. Patten BM, Barry A. The genesis of exstrophy of the bladder and epispadias. Am J Anat 1952;90:35.
4. White P, Lebowitz RL. Exstrophy of the bladder. Radiol Clin North Am 1977;15:93.