Diagnostic Challenges and Management of Urachal Malformations in an Infant.

Background: The urachus is a vestigial remnant of the allantois which naturally degenerates after birth. Failure of closure of the urachus can result in urachal malformations, with the most common being a urachal cyst. Diagnosing a urachal cyst is challenging due to its diverse presentations, often leading to misdiagnosis. Although they are often asymptomatic, urachal cysts can be significant because they can lead to complications. Case Report: We report a late preterm male infant born at 36 weeks + 5 days, in whom an antenatal anomaly scan revealed a unilocular intra-abdominal cyst adjacent to the bladder. Postnatal ultrasound kidney, ureter, and bladder (KUB) at 3 days of age demonstrated a cystic structure anterior and superior to the bladder, accompanied by mild bilateral hydronephrosis. A voiding cystourethrogram (VCUG) at 2 weeks revealed a cystic mass connected to the bladder by a fistulous tract, raising differential diagnoses of urachal cyst, bladder diverticulum, or incomplete bladder duplication. At 2 months, diagnostic cystoscopy and laparoscopy were performed. Cystoscopy showed a small opening at the bladder dome, while laparoscopy identified a 5 × 5-cm cyst extending from the bladder dome to the umbilicus. The cyst was excised laparoscopically, and bladder repair was completed. Histopathology revealed benign urothelium with mild chronic inflammation and a muscular wall, suggestive of a urachal diverticulum. Postoperative recovery was uneventful, and follow-up imaging demonstrated normal bladder morphology and renal function. Conclusions: Our case supports the efficacy of diagnostic and therapeutic laparoscopy in accurately diagnosing urachal anomalies, aiding in treatment decisions, and preventing future complications.