Infected patent urachus


  • A 55 years old man
  • No known medical illness
  • Presented with umbilical discharge for 3 weeks
  • Feeling feverish on and off
  • Having pain for the past few days
  • Clinically pus discharge seen from umbilibus

Ultrasound findings:

  • There is a rounded hypoechoic subcutaneous lesion with internal echoes seen immediately posterior to the umbilical opening, measuring at 2.4 x 2.1cm.
  • It appears continuous to an intra-abdominal component, which appears tubular and elongated. It can be seen coursing along the posterior aspect of the anterior abdominal wall until the urinary bladder dome region.
  • No vascularity or calcification noted within either the subcutaneous or intra-abdominal component.
  • The urinary bladder dome appears to have a thin cranial protrusion. Possible communication is visualised between this thin cranial urinary bladder protrusion and the tubular structure described above.

CT scan findings:

  • There is an elongated fluid-filled tubular track appearing continuous from the dome of the urinary bladder until the umbilicus.
  • It has irregular wall and measures at about 12.7cm in cranio-caudal length.
  • A cystic lesion is seen at the umbilicus itself measuring at 2.2 x 1.8 x 1.9cm (AP x W x CC) which appears continuous with the tapered part of the track.
  • Streakiness of the surrounding fat plane is also seen along the length of the track.
  • Both kidneys are normal in size and location. Single ureters are seen bilaterally, which appear to insert normally into the urinary bladder. No urinary tract stone seen.

Diagnosis: Infected patent urachus.


  • The urachus is a ductal remnant that arises embryologically, originating from the involution of the allantois and cloaca and extending between the bladder dome and the umbilicus.
  • During normal gestational development, the urachus involutes and its lumen is obliterated, becoming the median umbilical ligament.
  • Congenital urachal anomalies result from a failure of the developing urachus to completely obliterate its lumen.
  • Four types urachal anomalies include: patent urachus (sometimes referred to as urachal fistula), urachal cyst, umbilical-urachal sinus, and vesicourachal diverticulum.
  • Undetected urachal anomalies may cause abdominal and/or urinary complications as a result of chronic urinary stasis, inflammation, and infection, predisposing the patient to potential morbidity and malignanc.
  • An infected urachal cyst can occur at any age.


Author: radhianahassan