The primary considerations and image guided diagnosis of an infected urachal cyst in a pediatric patient.

Urachal cyst is a rare condition that is typically asymptomatic and will often have symptomatology that is misdiagnosed or missed. A urachal cyst occurs in 1 out of 5000 live-births, but is only clinically relevant in 1 out of 150,000 of the population often as an incidental finding. The urachus is the embryological remnant of the allantois, which connects the apex of the bladder to the umbilicus, and usually fully obliterates to become the median umbilical ligament. Urachal defects are uncommon and cysts are usually asymptomatic until infection results. An infected cyst may present mimicking a wide range of intra-abdominal and pelvic disorders, and accurate diagnosis is often delayed. Children may present with umbilical discharge; adults often have hematuria. Computed tomography (CT) and ultrasound are ideally suited for demonstrating urachal remnant diseases; however, infected urachal cysts commonly display increased echogenicity with ultrasoundsography and thick-walled cystic or mixed attenuation with CT. Drainage and excision of the urachal remnant is the definitive treatment.