Giant anterior urethral diverticulum with a calculus masquerading as left inguinal hernia: A missed diagnosis, a lesson to learn.

Congenital anterior urethral diverticulum is an infrequent but important cause of infravesical obstructive uropathy in children. Clinical spectrum usually includes obstructive or irritative urinary symptoms or penile ballooning during the act of micturition. We share our experience in a case of giant anterior urethral diverticulum with a contained calculus presenting as a huge inguino-scrotal swelling and masquerading as left inguinal hernia. The fluctuation in the size of the swelling related to the act of micturition was mistaken for cough impulse. He was subjected to a left inguinal herniotomy, following which he developed urine leak from the surgery wound and was subsequently referred to our centre for further management. The importance of a detailed history, meticulous physical examination, and diagnostic imaging has been stressed. The surgical approach in such cases has also been highlighted.

INTRODUCTION

Anterior urethral diverticulum is the most common cause of infravesical obstructive uropathy in children after posterior urethral valves. The usual presenting spectra include a poor urinary stream, post-micturition drip-incontinence, recurrent episodes of urinary infections due to persistent stasis, and penile ballooning during micturition, which deflates with dribbling of urine from the external meatus on mild digital pressure.[1]

We share our experience with an unusual case of huge anterior urethral diverticulum, which was large enough to involve the left inguinoscrotal region. The condition was inadvertently operated for left inguinal hernia.

CASE REPORT

A 3-year-old boy presented with a large left-sided hemi-scrotal swelling and a history of urine discharge from the suture line of left inguinal herniotomy [Figure 1a]. The urinary leak was exacerbated during and immediately after micturition.

Figure 1

Clinical Picture (a) depicting a large scrotal swelling, left inguinal herniotomy scar with urine discharge. (b) Micturating film of a voiding cystourethrogram revealing a large anterior urethral diverticulum arising from the bulbar urethra, mildly dilated posterior urethra, and bilateral grade IV vesicoureteric reflux

On detailed evaluation, it was elicited that the boy had a history of poor urinary stream since birth, which was neglected. Three months back, an intermittent swelling was observed in the left inguino-scrotal region. The fluctuation in size of the swelling was related to micturition and not to cough impulse. However, the condition was misdiagnosed as left inguinal hernia, and left-inguinal herniotomy was performed by another surgeon. Urine discharge from the surgical site was noted from the first post-operative day. He also had recurrence of scrotal swelling. The swelling was tense, non-tender, with limited mobility and involved the upper half of left hemi-scrotum and reached up to the midline, base of penis, extending cranio-laterally up to the pubic tubercle. On exerting pressure, the swelling disappeared with dribbling of urine from the external meatus and from the inguinal wound and reappeared at the next act of micturition. A hard oval structure resembling a calculus could be palpated within the swelling once deflated.

Sonography revealed dilatation of both the ureters in the lower half. Voiding cystourethrogram (VCUG) revealed the presence of a urethral diverticulum arising from the bulbar urethra with bilateral Grade IV vesicoureteric reflux [Figure 1b]. The posterior urethra was also mildly dilated. Urinary bladder was normal. The typical description of an acute angle forming between the proximal part of dilated portion and the ventral floor was conspicuous by its presence.

A midline incision was made from the mid-penile region to the middle of the scrotal raphe [Figure 2a]. A thick-walled diverticulum with a contained stone was appreciated in close proximity to the penile urethra. The diverticulum was extending beyond the confines of the corpus spongiosum into the left inguinoscrotal region. The diverticulum was canulated with an infant feeding tube to facilitate dissection and skeletonised along with the cutaneous fistulous tract communicating with the herniotomy incision [Figure 2b]. On opening the diverticulum, an elliptical mustard-colored calculus about 1 × 0.8 × 0.7 cm was identified [Figure 2c]. The diverticulum was opening into the ventral surface of the bulbar urethra with a narrow mouth (0.7 × 0.6 cm). A lip of tissue was appreciated along the mouth of the diverticulum. The fistula was disconnected from the inguinal region and the wound was repaired. The diverticulum was divided at its neck and the bulbar urethra was repaired with 5-0 vicryl over a no. 8 silicone catheter. The postoperative recovery was uneventful. The urinary catheter was removed on 7thpostoperative day. Postoperative urinary stream was good.

Figure 2

(a) Operative picture: Exposure by a midline incision extending from the mid-penile region to the middle of scrotal raphe. Urethral diverticulum is seen. (b) Canulation of the diverticulum by an infant feeding tube through the inguinal opening. (c) The two limbs of the infant feeding tube are depicting the communication of the diverticulum with the urethra

Histopathology of the diverticulum wall revealed all the layers of the urethra (true diverticulum) with mucosal ulcerations and chronic inflammatory cell infiltrates and congested blood vessels in the muscular layer. The sections from the portion of the diverticulum extending into the inguinal region revealed a fibrous wall lined by ulcerated squamous epithelium (pseudodiverticulum) with features of chronic inflammation.

DISCUSSION

We could not find such a huge anterior urethral diverticulum presenting as inguino-scrotal swelling in English literature. This patient had a history of poor urinary stream since birth, which was the first clue. The fluctuation in the size of the swelling was related to the act of micturition and was not a cough-impulse. The patient also complained of dribbling of urine from the meatus on digital manipulation, which was associated with resolution of the swelling and the feeling of a calculus.

Probable injury to the wall of the diverticulum during the attempt to perform inguinal herniotomy resulted in persistent urine leak from the site of herniotomy. The overall histopathology was consistent with features of a true diverticulum; the scarred wall of the diverticulum at the site of injury revealed features of a pseudodiverticulum.

Anterior urethral diverticulum, although rare, is an important cause of congenital urethral obstruction. It develops as blind-ending out-pouching on the ventral surface of the anterior urethra; most commonly between the bulbous and mid-penile urethra. Anterior urethral diverticulum near the corona has also been reported. Morphologically, it can be classified into saccular or globular variety, the former being much more common. A lip of tissue is usually present around the diverticulum, which rises into the urethral lumen as the diverticulum fills with urine during the act of micturition and causes ’valve-like’ obstruction.

Multiple etiologies have been proposed to explain the genesis of the diverticulum and include a ruptured syringocoele, incomplete hypospadias, cystic dilatation of the peri-urethral glands, focal mal-development of the corpus spongiosum, incomplete fusion of a segment of urethral plate, sequestration of an epithelial nest after closure of urethral folds, or the presence of epidermal pockets communicating with the ventral urethral wall.[23]

Presenting symptoms include poor urinary stream, postmicturition dribbling, recurrent episodes of urinary infections or a ’tell-tale’ ballooning of the penis at the time of micturition, which deflates with mild digital pressure.[1] Obara et al., reported a neonate presenting with an abdominal wall urinoma caused by the rupture of an anterior urethral diverticulum.[4] Stone formation in the diverticulum consequent to urinary stasis has been reported occasionally.[5] Diagnosis is clinical and supported by radiological investigations such as a VCUG or a retrograde urethrography (RGU). A VCUG also provides additional information about the status of upper tracts. Cystourethroscopy is both diagnostic as well as therapeutic. A diagnostic cystourethroscopy would reveal an outpouching from the ventral urethral wall with a rim proximally and distally. Ladwig et al., reported the first case of antenatal sonographic diagnosis of congenital anterior urethral diverticulum at 19 weeks of gestation.[6]

Management options are multiple and depend upon the size of the diverticulum and the degree of obstruction. Manual digital perineal compression may be advised to take care of urinary stasis. Transurethral resection of the distal obstructing lip may be sufficient in cases with small, well-supported diverticulae. Plication of redundant diverticular wall is yet another option. However, open diverticulectomy and anatomic reconstruction is recommended for large diverticulae. Urinary diversion in the form of supra-pubic cystostomy or vesicostomy may be needed to allow severe back-pressure changes to settle.

CONCLUSION

The authors wish to emphasize that all inguinal swellings should not be considered as an inguinal hernia. The development of penile ballooning during micturition that empties with digital manipulation and the tactile sensations of associated calculi, if any, is a definitive sign of anterior urethral diverticulum.

A huge diverticulum as in the index case is best managed with open diverticulectomy with primary repair. The procedure addresses the issue of redundant diverticular wall and is associated with promising results.