Urachal Remnant Abscess

Urachal Remnant Abscess
Published on Diagnostic Imaging (http://www.diagnosticimaging.com)
Urachal Remnant Abscess
Case Studies [1] | September 05, 2013
By Arti Chaturvedi, MD [2]
Case History: An 18-year-old boy presented to the surgery outpatient clinic with a one-week history
of a painful swelling at the umbilicus with purulent discharge.
Case History: An 18-year-old boy presented to the surgery outpatient clinic with a one-week history
of a painful swelling at the umbilicus with purulent discharge.
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Urachal Remnant Abscess
Published on Diagnostic Imaging (http://www.diagnosticimaging.com)
FIGURE 1
Ultrasound revealed a bilobed cystic lesion under the umbilicus with echogenic contents in the
umbilical cleft and relatively hypoechoic contents in the deeper component of the collection (Fig1).
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Urachal Remnant Abscess
Published on Diagnostic Imaging (http://www.diagnosticimaging.com)
FIGURE 2
A contrast CT of the abdomen revealed a lobulated collection under the umbilicus with thick
marginal enhancement (Fig 2).
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Urachal Remnant Abscess
Published on Diagnostic Imaging (http://www.diagnosticimaging.com)
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Urachal Remnant Abscess
Published on Diagnostic Imaging (http://www.diagnosticimaging.com)
FIGURE 3
The posterior margin of the collection was closely applied to the urachus which showed mild focal
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Urachal Remnant Abscess
Published on Diagnostic Imaging (http://www.diagnosticimaging.com)
FIGURE 4
Rest of the urachus was best visualized on sagittal reformatted images as a thin isodense cord
extending from the umbilical collection till the bladder vault (arrowed in Fig 4).
Diagnosis: Urachal remnant abscess
An imaging diagnosis of an urachal abscess draining through the umbilicus was made, most likely
due to an infected urachal cyst. The patient was treated with surgical drainage under antimicrobial
cover followed by complete excision of the cyst. Total removal of the cyst wall is essential to avoid
reinfection. Reinfection rates are as high as 30 percent in incompletely treated cases.
The urachus is a fibrous cord extending from the bladder vault till the umbilicus and is the vestigial
remnant of the urogenital sinus and allantois. Persistence of all or part of the urachus can result in
congenital or acquired urachal remnant diseases. Congenital urachal remnants may present as a
patent urachus (50 percent), umbilical-urachal sinus (15 percent), vesicourachal diverticulum (3
percent to 5 percent) or an urachal cyst (30 percent) (Fig-5 - Courtesy reference 3 below)
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Urachal Remnant Abscess
Published on Diagnostic Imaging (http://www.diagnosticimaging.com)
FIGURE 5
Acquired remnant disorders are mainly due to infection or neoplasm. Infection within an urachal cyst
is uncommon with a peak incidence in infancy and then again in early adulthood. The adult
presentation may be a consequence of partial opening of the urachus which may have closed at
birth. Direction of drainage of infected urachal fluid depends on the type of urachal patency.
Umbilical urachal sinuses and infected cysts close to the abdominal wall will result in umbilical
discharge. Infected cysts close to the bladder and vesico-urachal diverticuli may present with urinary
symptoms. Uncommonly, a large infected cyst may rupture into the peritoneal cavity and cause
peritonitis.
Ultrasound and CT are both reliable modalities for diagnosis of urachal abscess. Demonstration of a
midline fluid containing structure within the anterior abdominal wall and extension into the umbilicus
with or without umbilical discharge is virtually diagnostic of a urachal abscess. In some complex
abscesses, the mixed echoes on USS and heterogeneous enhancement on CT may mimic a urachal
carcinoma and an image guided FNAC or biopsy is then indicated for definitive diagnosis and
therapeutic planning.
Arti Chaturvedi MD
Senior Consultant, Department of Radiodiagnosis
Fortis International Hospital, Noida, India
References:
1. Yu JS, Kim KW, Lee HJ, Yoon CS, Kim MJ. Urachal Remnant Diseases: Spectrum of CT and US
Findings. Radiographics March 2001; 21: 451-461.
2. Walker C A Case Report of Urachal Abscess: A Rare Differential in Adult Abdominal Pain. Hawaii
Med J. 2010 February; 69(2): 35–36.
3. Abscess of urachal remnants presenting with acute abdomen: a case series. Tazi F, Ahsaini M,
Khalouk. Journal of Medical Case Reports Journal of Medical Case Reports 2012, 6:226
doi:10.1186/1752-1947-6-226
4. Ash A, Gujral R, Raio C. Infected urachal cyst initially misdiagnosed as an incarcerated umbilical
hernia. J Emerg Med. 2012 Feb; 42(2):171-3.
Source URL: http://www.diagnosticimaging.com/case-studies/urachal-remnant-abscess
Links:
[1] http://www.diagnosticimaging.com/case-studies
[2] http://www.diagnosticimaging.com/authors/arti-chaturvedi-md
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