Figure 1
Fig. 1
Figure 1 shows the presence of a inhomogeneous collection, located above the antero-superior wall of the bladder.
Collection margins are irregular and the content presents some fluid portions.
Urachal abscess in a young man
SectionUroradiology & genital male imaging
Case TypeClinical Cases
AuthorsBattaglia V, Grigolini A, Calcagni F, Desideri I, Bartolozzi C
Connected authors
21 years, male
Clinical History
A 21-year-old obese man came to our attention with fever (38°) and lower abdominal pain.
Imaging Findings
US showed the presence, all along the inner portion of the anterior abdominal wall, of a partially fluid collection, with thickened walls, measuring about 13x7 cm. The collection was located cranially to the bladder dome, from which it seemed not detachable (Fig. 1, 2).
CT evaluation showed that the collection extended from the bladder dome, from which it did not appear clearly cleaved, to the umbilicus; the collection was confined in front by linea alba and behind by the parietal peritoneum. The collection was characterised by irregular and finely spiculated borders. Signs of inflammatory reaction of parietal peritoneum were present. Some air bubbles were appreciable within the collection (Fig. 3, 4).
A week after generic antibiotic therapy, control CT showed the partial reduction of the lesion (4x4x10), characterised by a central, hypodense area, and the reduction of the inflammatory process of the peritoneum. A thin communication between the collection and the bladder was appreciable (Fig. 5, 6).
CT evaluation showed that the collection extended from the bladder dome, from which it did not appear clearly cleaved, to the umbilicus; the collection was confined in front by linea alba and behind by the parietal peritoneum. The collection was characterised by irregular and finely spiculated borders. Signs of inflammatory reaction of parietal peritoneum were present. Some air bubbles were appreciable within the collection (Fig. 3, 4).
A week after generic antibiotic therapy, control CT showed the partial reduction of the lesion (4x4x10), characterised by a central, hypodense area, and the reduction of the inflammatory process of the peritoneum. A thin communication between the collection and the bladder was appreciable (Fig. 5, 6).
Discussion
Urachal abnormalities result from the incomplete regression of the foetal urachus.
They are more common in children than in adults, due to urachal obliteration in early infancy [1]. This fact may be interpreted as the evidence of the existence of congenital and acquired forms of urachal disease, with acquired disease representing the partial reopening of the channel which is believed to have closed at birth [2, 3].
There are five types of urachal abnormalities: 1) patent urachus, in which the entire tubular structure fails to close; 2) urachal cyst, in which both ends of the canal close leaving an open central portion; 3) urachal sinus, which drains proximally into the umbilicus; 4) vescicourachal diverticulum, where the distal communication to the bladder persists; and 5) alternating sinus, which can drain to either bladder or umbilicus [4]. The incidence of UC in adults is unknown but it is rare. It is more common in men than women [5, 6]. Modes of presentation of urachal anomalies in adults differ from those seen in children. In adults, the commonest variety is urachal cyst (UC), with infection being usual mode of presentation [5, 7]. The route of infection is haematogenous, lymphatic, direct or ascending from the bladder. The commonly cultured microorganisms from the cystic fluid include Escherichia coli, Enterococcus faecium, Klebsiella pneumoniae, Proteus, Streptococcus viridans and Fusobacterium [6, 7].
Clinical symptoms are non-specific, as UC are largely asymptomatic until they become infected. The most common symptoms of infected UC include fever, lower abdominal pain, dysuria, periumbilical erythema and tender midline infraumbilical mass. Rarely, the UC may be complicated by umbilical discharge and sepsis.
For establishing the diagnosis, ultrasound examination and CT scan of the lower abdomen are useful tools, especially in showing the relationship between the urachus and the urinary bladder or umbilicus [8, 9].
A vesicourachal diverticulum is usually discovered incidentally at US, manifesting as an extraluminal protruding, fluid-filled sac, joining the umbilical region.
At axial CT, it appears as a midline cystic lesion just above the anterosuperior wall of the bladder. Signs of infection are represented, at US, by the presence of thickening of collection walls; at CT the enhancement of collection walls can be appreciable, as well as air bubbles within the fluid content [10].
Although the differentiation between infection and urachal carcinoma is difficult because both infection and carcinoma can present as a solid mass with adjacent organ involvement, the presence of calcification is suggestive of carcinoma [11].
They are more common in children than in adults, due to urachal obliteration in early infancy [1]. This fact may be interpreted as the evidence of the existence of congenital and acquired forms of urachal disease, with acquired disease representing the partial reopening of the channel which is believed to have closed at birth [2, 3].
There are five types of urachal abnormalities: 1) patent urachus, in which the entire tubular structure fails to close; 2) urachal cyst, in which both ends of the canal close leaving an open central portion; 3) urachal sinus, which drains proximally into the umbilicus; 4) vescicourachal diverticulum, where the distal communication to the bladder persists; and 5) alternating sinus, which can drain to either bladder or umbilicus [4]. The incidence of UC in adults is unknown but it is rare. It is more common in men than women [5, 6]. Modes of presentation of urachal anomalies in adults differ from those seen in children. In adults, the commonest variety is urachal cyst (UC), with infection being usual mode of presentation [5, 7]. The route of infection is haematogenous, lymphatic, direct or ascending from the bladder. The commonly cultured microorganisms from the cystic fluid include Escherichia coli, Enterococcus faecium, Klebsiella pneumoniae, Proteus, Streptococcus viridans and Fusobacterium [6, 7].
Clinical symptoms are non-specific, as UC are largely asymptomatic until they become infected. The most common symptoms of infected UC include fever, lower abdominal pain, dysuria, periumbilical erythema and tender midline infraumbilical mass. Rarely, the UC may be complicated by umbilical discharge and sepsis.
For establishing the diagnosis, ultrasound examination and CT scan of the lower abdomen are useful tools, especially in showing the relationship between the urachus and the urinary bladder or umbilicus [8, 9].
A vesicourachal diverticulum is usually discovered incidentally at US, manifesting as an extraluminal protruding, fluid-filled sac, joining the umbilical region.
At axial CT, it appears as a midline cystic lesion just above the anterosuperior wall of the bladder. Signs of infection are represented, at US, by the presence of thickening of collection walls; at CT the enhancement of collection walls can be appreciable, as well as air bubbles within the fluid content [10].
Although the differentiation between infection and urachal carcinoma is difficult because both infection and carcinoma can present as a solid mass with adjacent organ involvement, the presence of calcification is suggestive of carcinoma [11].
Differential Diagnosis List
Reported findings suggested the diagnosis of an urachal abscess.
Bladder diverticulum
Urachus carcinoma
Final Diagnosis
Reported findings suggested the diagnosis of an urachal abscess.
References
[1] Hammond G, Yglesias L, Davis JE (1941) The urachus, its anatomy and associated fascia. Anat Rec 80:271-274
[2] Lees VC and Doyle PT (1991) Urachal cyst presenting with abscess formation. Journal of the Royal Society of Medicine 84: 367 (PMID: 2061906)
[3] Blichert-Toft M, Kock F, Nielson OV (1973) Anatomic variations of the urachus related to clinical appearance and surgical treatment of urachal disorders. Surg Gynecol Obstet 137:51
[4] Ekwueme KC, Parr NJ (2009) Infected urachal cyst in an adult: a case report and review of the literature. Cases Journal 2: 6422 (PMID: 19829803)
[5] Risher WH, Sardi A, Bolton J (1990) Urachal abnormalities in adults: the Ochsner experience. South Med J 83:1036-1039 (PMID: 2402647)
[6] Ashley RA, Inman BA, Routh JC et al (2007) Urachal anomalies: a longitudinal study of urachal remnants in children and adults. J Urol 178:1615-1618 (PMID: 17707039)
[7] Yoo KH, Lee SJ, Chang SG (2006) Treatment of infected urachal cysts. Treatment of infected urachal cysts. Yonsei Med J 47: 423-427 (PMID: 16807994)
[8] Cilento BG Jr, Bauer SB, Retik AB (1998) Urachal anomalies: defining the best diagnostic modality. Urology 52: 120-2 (PMID: 9671882)
[9] Chiang PH, Chou YH, Huang CH (1990) Urachal anomalies: acquired patent urachus and giant urachal cyst-2 cases report. Kaohsiung J Med Sci 6:201-5 (PMID: 2342162)
[10] Yu JS, Kim KW, Lee HJ, et al (2001) Urachal remnant diseases: spectrum of CT and US findings. Radiographics 21:451-61 (PMID: 11259707)
[11] Nimmonrat A, Na-ChiangMai W, Muttarak M (2008) Urachal abnormalities: clinical and imaging features. Singapore Med J 49:930-5 (PMID: 19037562)
Case information
| URL: | https://www.eurorad.org/case/9077 |
| DOI: | 10.1594/EURORAD/CASE.9077 |
| ISSN: | 1563-4086 |
Figure 2
Fig. 2
Figure 2 demonstrates that the collection does not present signs of conspicuous vascularisation.
Figure 3
Fig. 3
CT examination confirmed the presence of the suspected collection, whose lower margin was not clearly cleavable from the bladder. The superior margin was located at the level of the umbilicus.
Figure 4
Fig. 4
Axial baseline CT images showed clear signs of peritoneum inflammatory reaction all around the collection, that presented inhomogeneous content and small air bubbles within.
Fig. 1
Figure 1 shows the presence of a inhomogeneous collection, located above the antero-superior wall of the bladder.
Collection margins are irregular and the content presents some fluid portions.
Fig. 2
Figure 2 demonstrates that the collection does not present signs of conspicuous vascularisation.
Fig. 3
CT examination confirmed the presence of the suspected collection, whose lower margin was not clearly cleavable from the bladder. The superior margin was located at the level of the umbilicus.
Fig. 4
Axial baseline CT images showed clear signs of peritoneum inflammatory reaction all around the collection, that presented inhomogeneous content and small air bubbles within.