Medical Student Pearl by Alexander MacPherson
MD Candidate, Class of 2024
Dalhousie University New Brunswick
Reviewed by Dr. B Ramrattan
Copy Edited by Dr. J Vonkeman
Pdf Download: EMSJ Understanding Urachal Anomalies by AMacpherson
Case Presentation
17-year-old male presents to the emergency room with what he tells you is a pop bottle amount pus-like fluid discharging from his belly button. He appears well and said that this has happened before, but it was never in this amount. He and his family members are, however, concerned as to what may be causing this unusual presentation. Patient denies any past abdominal surgeries or piercings.
Physical Exam
- Vitals: HR 70, BP 118/78, RR 14, T 37.3°C
- Tenderness in the periumbilical region
- Discharge of whitish, mucus-like liquid.
- Red, dome shaped swelling at centre of umbilicus.
Differential Diagnosis [1]
- Urachal anomaly
- Abscess
- Benign lesion (hamartomas, pyogenic granulomas etc.)
- Primary malignancy (urachal adenoma, melanoma, squamous cell carcinoma and basal cell carcinoma).
- Metastatic lesion
- Omphalitis
Common Clinical Findings of Urachal Anomalies [1]
Urachal anomalies when found in children typically present with:
- Umbilical drainage
- Abdominal pain
- Abnormal appearance of the umbilicus, with a palpable mass
- Infection
- Incidental finding
Urachal anomalies when found in adulthood typically present with:
- Hematuria
- Pain
- Dysuria
- Incidentally
Investigations
- The primary investigation for a urachal anomaly is through Imaging.
- Most urachal remnants are diagnosed via abdominal ultrasonography.
- CT abdomen, MR abdomen and Voiding Cystourethrography (VCUG) are also used to detect and diagnose urachal anomalies and to confirm that there are no associated genitourinary tract abnormalities. [1,2].
- Our patient received an ultrasound and went on for a CT abdomen to confirm the diagnosis of urachal cyst.
Treatment
- Surgical resection seems to be the most definitive way to manage and prevent the return of symptoms. It is also important to note that adults presenting with urachal anomalies are at a considerable progressive risk for cancer and if not removed should undergo routine screening.
- Early removal of urachal remnants at first diagnosis are deemed to be best at preventing future morbidity by some studies, while others recommend that children who are experiencing asymptomatic lesions do not benefit from prophylactic excision [1,2,3]
- Our patient was referred to general surgery and the urachal cyst was excised.
Background on Urachal Anomalies
During embryologic development the allantois has a connection to the apex of the fetal bladder. This connection is called the urachus and allows for fetal bladder emptying [4]. In a normally developing fetus, the bladder descends into the pelvis. This decent of the bladder stretches the urachus and its lumen is eventually obliterated. The now obliterated urachus is a fibrous cord that is called the median umbilical ligament and continues to be connected to the umbilicus and the bladder. This process, like any other, can be disrupted [5].
The disruption can be divided into several urachal anomalies based on the amount of and where the residual tissue is located (Figure 1):
- Patent urachus: A complete failure of closure of the lumen forming a tubular connection between the bladder and umbilicus. Allows for urine to drain through the umbilicus.
- Bladder diverticulum: Extra tissue present at the bladder end but does not continue to the umbilicus.
- Umbilical polyp: Extra tissue and patency at the umbilical end that does not continue to the bladder.
- Urachal cyst: An area of patency in between the bladder and umbilicus that does not communicate with either [1,4].
Figure 1. Urachal anomaly types. Accessed from UpToDate [6]
An Important Note on Malignancy
- Although there have been no reports of urachal adenocarcinoma in the urachal anomalies resected from children a longitudinal study by Ashley et al (2007) found that 51% of those resected from adults showed evidence of malignancy. It was also determined that age >55 and hematuria were the strongest predictors for malignancy [2].
- A comprehensive review performed by Gleason et al (2013) however determined that urachal anomalies are more common that previously reported and that the number needed to excise to prevent one case of urachal adenocarcinoma was 5,721 [3]
References
- Palazzi, D. L., & Brandt, M. L. (2021, August 27).Care of the umbilicus and management of umbilical disorders. UpToDate. Retrieved April 16, 2022, from https://www.uptodate.com/contents/care-of-the-umbilicus-and-management-of-umbilical-disorders
- Ashley RA, Inman BA, Routh JC, Rohlinger AL, Husmann DA, Kramer SA. Urachal anomalies: a longitudinal study of urachal remnants in children and adults. J Urol. 2007 Oct;178(4 Pt 2):1615-8. doi: 10.1016/j.juro.2007.03.194. Epub 2007 Aug 16. PMID: 17707039.
- Gleason JM, Bowlin PR, Bagli DJ, Lorenzo AJ, Hassouna T, Koyle MA, Farhat WA. A comprehensive review of pediatric urachal anomalies and predictive analysis for adult urachal adenocarcinoma. J Urol. 2015 Feb;193(2):632-6. doi: 10.1016/j.juro.2014.09.004. Epub 2014 Sep 16. PMID: 25219697.
- Briggs KB, Rentea RM. Patent Urachus. [Updated 2021 Jun 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557723/
- Naiditch, Jessica A.; Radhakrishnan, Jayant; Chin, Anthony C.(2013). Current diagnosis and management of urachal remnants. Journal of Pediatric Surgery, 48(10), 2148–2152. doi:10.1016/j.jpedsurg.2013.02.069
- Retrieved from: https://www.uptodate.com/contents/image?imageKey=PEDS%2F79324&topicKey=PEDS%2F5009&search=urachal+cyst+infection&rank=1%7E150&source=see_link