CASE 10030 Published on 26.04.2012

Urachal cyst infection

Section

Uroradiology & genital male imaging

Case Type

Clinical Cases

Authors

Caetano J

; Email:joanna.caetano@hcuge.ch
Patient

82 years, male

Categories
Area of Interest Urinary Tract / Bladder ; Imaging Technique CT
Clinical History
An 82-year-old male patient suffering from Parkinson's disease and dementia presented at the emergency department with fever, nausea, and abdominal pain. Laboratory results showed leukocytes within normal range (8.4G/l) associated with increased segmented neutrophils (77%) and elevated CRP (404.3 mg/l). Patient had a urinary catheter in place upon arrival.
Imaging Findings
A thoracic and abdominal non-contrast-enhanced CT examination for renal insufficiency was performed in the emergency department in search of a source of infection. The abdominal images showed a fluid-filled mid-line structure with a tubular extension from the umbilicus to the anterior-superior aspect of the bladder. This structure presented thickened walls and fat stranding surrounding it. Small bowel distension was also noted in favour of a paralytic ileus. Patient was treated with conservative antibiotherapy, follow-up ultrasound showed no abnormalities.
Discussion
The urachus, also known as the medial umbilical ligament, is a tubular structure extending from the umbilicus to the antero-superior aspect of the bladder. It is an embryologic remnant of the cloaca (cephalic part of the urogenital sinus) and the allantois (derivative of the yolk sac). This structure normally involutes before birth but in some cases remnants remain. There are four entities in urachal remnant disease; 1) patent urachus, 2) umbilical-urachus sinus, 3) vesico-urachal diverticulum, and 4) urachal cyst. [1] A patent urachus is a tubular connection between the bladder and umbilicus. An umbilical-urachus sinus is a dilatation of the urachus at the umbilical end. A vesico-urachal diverticulum is a dilatation of the urachus that communicates with the bladder dome. A urachal cyst occurs when the urachus closes at both ends (bladder and umbilicus) but remains open between the two extremities, usually the lower third and less frequently the upper third. [1, 2]

The main pathologies encountered in urachal remnant disease are infectious and tumoral. Patients present with non-specific signs making the diagnosis of this entity a real clinical challenge. Imaging modalities such as ultrasound and CT can aid in the diagnosis. CT findings include the presence of a fluid-filled structure situated on the midline with a tubular remnant extending in both directions, towards the umbilicus and the bladder dome. CT is particularly useful as it allows analysis in different planes of the structure, however, the differential diagnosis between an infectious and tumoral aetiology, urachal carcinoma, is not evident. The presence of a nodular wall, calcifications and the absence of inflammatory changes adjacent to the structure are in favour of a tumoral origin. Percutaneous needle biopsy or fluid aspiration may become necessary to differentiate between the two entities. An infected cyst can be treated by drainage followed by surgical resection in order to avoid further complications. [1, 2]
Differential Diagnosis List
Urachal cyst infection
Bladder diverticulum
Omphalomesenteric duct cyst (=vitelline cyst)
Mesenteric cyst
Meckel’s diverticulum
Umbilical hernia
Final Diagnosis
Urachal cyst infection
Case information
URL: https://www.eurorad.org/case/10030
DOI: 10.1594/EURORAD/CASE.10030
ISSN: 1563-4086