Congenital midline abdominal defect in which the bladder mucosa is everted "inside out" to the abdominal wall.
Other malformations may accompany, such as epispadias, cloacal exstrophy and cryptorchidism.
More common in males (male-to-female ratio 2:1).
Incidence is 1 in 30,000 births and risk for having a second child with the disease is 1 in 100 and if one parent has the disease is 1 in 70.
Urinary tract is open from urethral meatus to the umbilicus and the mucosa connects to the skin (image A).
At birth, bladder mucosa is normal but gradually develops inflammation, ulceration and metaplasia.
With time, mucosa is replaced by metaplastic keratinizing squamous epithelium or intestinal type epithelium (image B).
Patients with long-standing exstrophy are at increased risk for cancer, particularly adenocarcinoma.
Risk diminished with early surgical intervention.