Abstract
Urachal sinus usually presents with umbilical discharge and the opening can rarely be located between the umbilicus and the symphysis pubis and the so called suprapubic sinus (SPS). There is another different entity of cases reported in literature with a similar presentation but with an opening anywhere between the umbilicus and symphysis pubis but differs from SPS in the pathway of the tract and the epithelial lining. We report a case of a 2-year-old boy presenting with a prepubic sinus that was managed with surgical excision. After a thorough literature review, we compare our case to other prepubic and SPS.
Keywords: congenital disorders, paediatric surgery, urological surgery
Background
This is a rare pathology in children with a sinus opening in the lower abdomen. Very few data in literature had reported this. To our knowledge, this is the first article to collect all cases of both prepubic and suprapubic sinuses (SPS) with a thorough literature review in one article.
Case presentation
A 2-year-old boy was referred electively with a small skin opening 1 cm above the root of the penis since birth discharging what his mother explained as pus or offensive mucoid material on irregular basis. There was no history of urine or any intestinal content coming out from this opening. Apart from cow milk allergy, he had an uneventful prenatal and postnatal history.
On examining, a tiny sinus was located 1 cm above the pubis with no signs of inflammation around it (figure 1A). We could not palpate any tract deeply under the skin, however on squeezing, pus/mucoid like discharge was released (figure 1B).
Figure 1.
(A): Prepubic sinus without discharge. (B): Prepubic sinus with discharge after squeezing. (C): Probe in the sinus. (D): Cannula inserted in the sinus to facilitate dissection.
Investigations
Ultrasound of the urinary system was normal and could not visualise any subcutaneous tract or cysts underneath the sinus. Culture and sensitivity of the discharge showed heavy growth of enterococcus and coagulase negative staphylococci sensitive to co-amoxclav.
Differential diagnosis
Final diagnosis in our case was prepubic sinus based on the literature classification that depends mainly on the epithelial lining and the pathway of the tract. However. SPS is among the differential diagnosis.
Treatment
Under general anaesthesia, as a day case surgery, the sinus was easily probed using a lacrimal probe without inducing any false passage (figure 1C). Then a 22 G cannula was inserted in the sinus and passed for 2.5 cm before ending blindly. The contrast was injected and the sinogram showed no communication with the bladder or with any underlying cysts. Elliptical transverse incision was done surrounding the sinus involving the tract through the skin and subcutaneous all the way down to symphysis pubis where the tract ended blindly (figure 1D). The urinary bladder was filled with saline using a Foley catheter size 8 French to exclude any leakage. At the end, the sinus was transfixed and ligated using a 3/0 absorbable suture and sent for histology.
Outcome and follow-up
The patient had a smooth postoperative recovery and follow-up. Three months postoperatively, he had a good looking scar in the prepubic area with no evidence of recurrence, urinary leakage or wound infection.
The histopathological report of the specimen showed squamous epithelium lining the sinus with no evidence of transitional or urothelial epithelium.
Discussion
Literature review for any pathology associated with a ‘sinus’ located between the root of the penis and the umbilicus revealed two different types of pathologies an SPS and a congenital prepubic sinus (CPS). The former is related to the urachus which is a fibrous vestigial remnant of the foetal allantois. Persistent urachal remnant occurs due to incomplete regression after birth.1 2 Urachal anomalies include patent urachus (most common), urachal sinus cyst, diverticulum3 and SPS. SPS was reported in three girls in literature. Their ages were 2, 4 and 8 .4–6 This sinus ended in the median umbilical ligament (urachal remnant) in the midline midway between the umbilicus and symphysis pubis and was lined by the transitional epithelium in two cases and by pseudostratified columnar non-ciliated epithelium in the third. Although SPS is a purely urachal abnormality, the CPS has been explained in literature by four different theories. In the first theory, CPS is due to defect of the midline abdominal wall closure at 4th week of gestation and the presence of diastasis in the symphysis pubis and squamous epithelium lining of the sinus can support this theory. However the presence of transitional epithelium in the deeper layer of the tract found in many cases is against this theory.7 8 In the second theory, CPS is formed due to dorsal urethral duplication which classified the sinus anatomically into three subtypes: type 1 is the channel that runs parallel to the normal urethra, type 2 is an epispadiac type of channel and type 3 is a dermoid sinus that simulates an accessory urethra. Finding squamous epithelium in many cases as the only epithelium lining the sinus is against this theory.9 In the third theory, there is a congenital fistula of primitive urogenital sinus which classified the sinus into three subtypes as well: type 1 is high sinus towards the urachal remnant, type 2; is middle sinus to the bladder and type 3 is low sinus to the prostatic urethra.10 The fourth theory is due to persistent cloacal remnant having three different types of epithelium as evidenced in some cases.7 9 According to our review of the literature and the data we found in our case we can suggest that our case can belong to the first theory mainly due to the type of epithelium lining the sinus.
First described by Campbell et al, CPS has been reported more frequently in the literature.7 Forty six cases have been reported with male predominance (25 men and 21 women), with age ranging between 1 month and 22 years.11 The most common presentation was discharge with or without inflammation of the surrounding skin. In other patients, the presentation was either external opening or groin swelling. The external opening is located in the suprapubic area (n=4), prepubic (n=19) on the dorsum of the penis (n=10), above the clitoris (n=8) and unspecified (n=5). The tract passed above the pubis in 17 cases, through the pubis in five cases and below the pubis in another seven cases to end into the bladder, umbilicus or retropubic space and unspecified (n=17). In more than half of the cases reported in literature, the distal end of the sinus ended in the bladder and the other half ended either in the retropubic space or the urethra.12
In this article, we report a case of a 2-year-old boy who presented with a sinus discharging mucoid material in the prepubic area 1 cm above the pubis (prepubic) but without previous infection of the surrounding skin, this is quite similar to the previously reported cases by others8 and similar to other 17 cases where the sinus tract ended above the pubis.9
The epithelial lining of the CPS in literature was either squamous epithelium (n=15) or transitional epithelium (n=7) while the majority of cases were lined with both transitional and squamous (n=20) and only in four cases, the lining epithelium was columnar or cylindrical (table 1). The lining epithelium in our case was a squamous epithelium one.
Table 1.
Congenital prepubic sinus reported cases12
| Year | Age | Gender | Opening | Symptom | Tract | Distal end | Histology |
| 1987 | 4m | F | Prepubis | Discharge | Above pubis | Bladder | Proximal transitional:distal squamous |
| 1987 | 6m | M | Prepubis | Opening | Above pubis | Bladder | Stratified squamous |
| 1987 | 2y | F | Above clitrois | Groin swelling | Above pubis | Bladder | Proximal transitional:distal squamous |
| 1989 | 18 m | F | suprapubis | Discharge | Below pubis | Bladder | transitional |
| 1990 | 10 m | F | Prepubis | Discharge | Above pubis | Bladder | Squamous |
| 1992 | 2m | M | Prepubis | Opening | Through pubis | Bladder | Transitional |
| 1992 | 2y | F | Prepubis | Discharge | Above pubis | Bladder | Pseudostratified |
| 1992 | 2y | F | Prepubis | Opening | Above pubis | Retropubic space | Transitional |
| 1993 | 1m | F | Prepubis | Discharge | Below pubis | Umbilicus | Proximal transitional: distal squamous |
| 1993 | 1m | F | Prepubis | Discharge | Above pubis | Umbilicus | Proximal transitional: distal squamous |
| 1993 | 4m | F | Above clitoris | Discharge | Above pubis | Umbilicus | Stratified squamous |
| 1994 | 11 m | M | Suprapubic | Discharge | Above pubis | Bladder | Proximal transitional: distal squamous |
| 1994 | 3y | M | Prepubis | Red & swollen | Above pubis | Bladder | Squamous |
| 1994 | 2m | F | Above clitoris | Discharge | Thorough pubis | Bladder | Stratified squamous |
| 1995 | 1y | F | Above clitoris | Discharge | ND | retropubic | Proximal transitional: distal squamous |
| 1996 | 8y | F | Above clitoris | Opening | Below pubis | Retropubic space | Proximal transitional: distal squamous |
| 1997 | 10 m | F | Above clitoris | Pustule | Below pubis | Urethra | Stratified squamous |
| 1997 | 10 m | M | Dorsal radix of penis | Discharge | Above pubis | Bladder | Proximal transitional: distal squamous |
| 1997 | 5y | M | Prepubis | Discharge | Above pubis | Bladder | Squamous |
| 1997 | 4y | M | Dorsal penile root | Discharge | Above pubis | Bladder | Stratified squamous |
| 1998 | 5y | M | Suprapubic | Discharge | ND | Abdominal wall | Squamous, Columnar |
| 2001 | 2m | F | Above clitoris | Discharge | ND | Bladder | Proximal transitional: distal squamous |
| 2001 | 3m | M | Prepubis | Discharge | ND | Bladder | Proximal transitional: distal squamous |
| 2001 | 1m | M | Prepubis | Discharge | ND | Bladder | Proximal transitional: distal squamous |
| 2001 | 14y | M | Dorsal penile root | Discharge | ND | Prepubic space | Proximal transitional: distal squamous |
| 2001 | 2m | F | Prepubis | Discharge | ND | Dorsal tunica albuigenea clitoris | Squamous |
| 2002 | 8m | M | Prepubis | Discharge | Below pubis | Prostatic urethra | Stratified squamous |
| 2002 | 5m | M | Prepubis | Discharge | ND | Pubic symphasis | Stratified squamous |
| 2002 | 5y | M | Prepubis | Discharge | ND | Retropubic space | Proximal ciliated columnar, middle transitional, distal stratified squamous |
| 2003 | 4y | F | Suprapubis | Discharge | ND | umbilicus | Transitional |
| 2003 | 2y | M | Dorsal radix of penis | Discharge | ND | Bladder | Proximal transitional:distal squamous |
| 2004 | 3m | M | Prepubis | Opening | Through pubis | Umbilicus | Proximal transitional: distal squamous |
| 2004 | 4y | F | ND | ND | ND | Bladder | Transitional |
| 2004 | 8y | M | Dorsal radix of penis | Discharge | Above pubis | Bladder | Stratified squamous |
| 2005 | 3y | M | Dorsal radix of penis | Discharge | ND | Pubic symphysis | Stratified squamous |
| 2006 | 12y | F | Above clitoris | Clitomegaly | ND | Retropubic space | Squamous |
| 2007 | 3y | M | Dorsal radix of penis | Discharge | Above pubis | Bladder | Proximal transitional: distal squamous |
| 2010 | 4m | M | Prepubis | Discharge | Above pubis | Bladder | Stratified squamous, transitional, cylindrical |
| 2011 | 4y | M | Dorsal radix of penis | Discharge | ND | Prepubic space | Squamous |
| 2013 | 9m | M | Dorsal radix of penis | Discharge | Below pubis | Bladder | Transitional |
| 2013 | 10 m | M | Prepubis | Discharge | Through pubis | Bladder | Proximal transitional: distal squamous |
| 2015 | 16y | F | ND | Clitoral and labial swelling | Through pubis | Bladder | Proximal transitional: distal squamous |
| 2015 | 22y | F | Prepubis | Fever+ abdominal pain | Below pubis | Bladder | Proximal transitional: distal squamous |
| 2015 | 3y | M | Prepubis | Discharge | Below pubis | Prepubic space | Proximal transitional: distal squamous |
| 2016 | 2y | F | Prepubis | Discharge | Above pubis | Umbilicus | Proximal transitional: distal squamous |
| 2017 | 2y | M | Dorsal radix of penis | Discharge | Below pubis | Prevesical space | Transitional |
| 2019 current case |
2y | M | Suprapubic | Discharge | Above pubis | Retropubic space | Squamous |
F, female; M, male; m, month; ND, not documented; Y, year.
In this case the patient had no previous history of skin infection which allowed proper assessment and elective admission for surgery. However, in case of acute infection, we suggest antibiotic treatment with/without drainage and then surgical excision once the infection subsides. Many cases were reported to have had surgical excision at the very early age of 1–4 months. We can attribute that to the recurrent attacks of skin infection which necessitate early intervention.
Learning points.
Suprapubic sinus and congenital prepubic sinus are two different pathologies but with quite similar presentation and lining epithelium.
The proper management is complete surgical excision of the sinus for histological assessment.
Adequate long-term follow-up is needed due to the lack of clarity of its embryological origin.
Footnotes
Contributors: Both authors have shared in the writing, revision and correction of this case report.
Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests: None declared.
Provenance and peer review: Not commissioned; externally peer reviewed.
Patient consent for publication: Obtained.
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