Urachal duct remnant is the most common congenital urachus anomaly; these anomalies are more common than previously thought, with more cases discovered incidentally, because of the increased use of cross-sectional imaging antenatally. Although an abnormal persistence of an embryologic communication between the bladder and the umbilicus is often recognized and managed in childhood, it may persist into adulthood, with a greater risk of morbidity. Patent urachus, a persistent tubular structure connecting the dome of the bladder to the umbilicus, represents 50% of urachal anomalies. It is usually detected neonatally because of leakage of the urine from the umbilicus. Of note, one-third of these cases occur in association with bladder outlet obstruction caused by posterior urethral valves or urethral atresia. The frequency of other urachal anomalies is as follows: urachal cyst (30%), umbilical–urachal sinus (15%) and vesicourachal diverticulum (3–5%). The sinus is a tract with a blind ending at the umbilicus. The diverticulum represents a distal dilation of the bladder directed towards, but not communicating with, the umbilicus; most diverticula are asymptomatic.
Congenital urachal anomalies that are detected early can benefit from an optimized management including surgical approach with a complete resection of the urachal remnant in cases when spontaneous resolution has failed; also laparoscopy is implemented for diagnosis and deals with urachal anomalies at different age group. At imaging, the different types of urachal anomalies have a distinct appearance; a patent urachus is recognized as an elongated patent connection between the bladder and the umbilicus, and an umbilical–urachal sinus is depicted as a blind focal dilation at the umbilical end, whereas a vesicourachal diverticulum is a focal outpouching at the vesical end. Urachal cysts are visualized as midline fluid-filled sacs most frequently located near the bladder dome. Complications of urachal anomalies have nonspecific clinical findings and can mimic other abdominal and pelvic lesions. Complications, such as infection and tumors, should be also recognized early to ensure optimal management. Understanding of the embryonic development of the urachus is necessary for the surgeons to diagnose the wide variety of urachal disease.
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