Year : 2006 | Volume
: 22 | Issue : 2 | Page : 148--149
Ventral urethral diverticulum of fossa navicularis
Dept. of Urology, St. Philomena's Hospital, Mother Teresa Road, Bangalore - 560 004, Karnataka, India
G-1 Aashraya Apts, 63 South Cross Road, Basavanagudi, Bangalore - 560 004
A rare case of ventral diverticulum of fossa navicularis was encountered in an adult. This has not been reported earlier in the urological literature.
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Vijayan P. Ventral urethral diverticulum of fossa navicularis.Indian J Urol 2006;22:148-149
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Vijayan P. Ventral urethral diverticulum of fossa navicularis. Indian J Urol [serial online] 2006 [cited 2020 Sep 21 ];22:148-149
Available from: http://www.indianjurol.com/text.asp?2006/22/2/148/26574
A 32-year old male presented to the urology clinic with a small boggy swelling of one year duration, on the under surface of the penis. He also noticed that manual pressure on the swelling resulted in escape of few drops of urine from the external urinary meatus. He had no urinary voiding symptoms and denied any history of infection, trauma or surgery to the urethra, except circumcision in his childhood for religious reasons. He was married and had one child.
Clinical examination revealed a circumcised male. The external urinary meatus (EUM) was normal in size and site. There was a soft swelling 0.75 x 0.75 cm on the ventral aspect of corona glandis. Few drops of urine could be expressed on manual compression of the swelling.
Uroflowmetry showed normal values. Routine urine analysis, microscopy, culture and biochemistry of the blood showed normal values. Voiding cystography and retrograde urethrography failed to reveal any communication between the normal urethra and the swelling described above. Contrast injection into the swelling to delineate was not employed. Sonourethrography was not available.
A clinical diagnosis of diverticulum of the urethra was made on clinical grounds, despite the fact there was no radiological proof.
Urethroscopy failed to reveal any abnormality. Surgery was decided upon, as the trickle of urine interfered with his religious practice. At operation, the fundus of the diverticulum was easily located and dissected free. The neck was seen to proceed distally and seemed to communicate with the floor of the fossa navicularis [Figure 1]. The fundus was opened [Figure 2] and attempts to pass a fine probe through the neck of the diverticulum failed. However, when methylene blue was injected into the fundus, the dye appeared at the external urinary meatus, thus demonstrating the fact that the sac did have a communication with the distal urethra, though it was small [Figure 3]. The neck was completely dissected free and it was divided at its junction with the fossa navicularis. The patient was left with an indwelling catheter, which was removed after 5 days. The postoperative period was smooth and following removal of catheter, he voided urine satisfactorily. Histology of the excised specimen showed it to have stratified squamous epithelium with fibromuscular surrounding tissues, confirming it to be a true diverticulum of the urethra. The patient was followed up for 2 years and remained symptom free.
Male urethral diverticulae are rare and have been described mostly in relation to the anterior urethra. More than 90% are of the acquired variety and result from trauma, instrumentation, surgery, suppuration and urethral calculus or stricture. The congenital variety being lined by urethral mucosa, also occurs in anterior urethra. The symptoms would depend on its location and size. Small urethral diverticulae may be incidental and remain unchanged in size over years. Several theories have been put forward to explain the embryological origin.
The urethral plate is tubularized by the fusion of inner genital folds and the edges of the plate. The fusion proceeds in a proximal to distal sequence.
Earlier theory stated that a solid ectodermal core developed in the centre of the glans penis, grew inward, parallel with and underlying the roof of the glandular urethra and canalized. The contiguous walls of the ectodermal sinus and the glandular urethra broke down to establish urethral continuity. The natural anastamosis of the lumena of both resulted in a capacious orifice and fossa navicularis. In some, the anastamosis might be incomplete in the deepest part of ectodermal sinus, giving rise to a small pit known as lacuna magna. If the sinus was abnormally long and the anastamosis incomplete, the lacuna became a dorsal diverticulum. However, the above theory was challenged by subsequent studies by Korzrack, who hypothesized that the entire urethra including the glans portion was formed by dorsal extension and disintegration of the urethral plate, combined with ventral growth and fusion of urethral folds. Animal studies showed that bladder epithelium differentiated into stratified squamous epithelium, thus proving that urothelium could be induced to express stratified squamous epithelium.
Common to these theories is the absence of the supporting corpus spongiosum, which allows ventral dilatation of diverticula lumen during voiding.
There is little or no literature on ventrally located diverticulum of the fossa navicularis. Gupta and Srinivas reported in a retrospective study, involvement of glanular urethra in one case out of 9 cases of congenital anterior urethral diverticulum in the paediatric age group. The diagnosis is often a clinical one i.e., a palpable swelling and compression, resulting in escape of urine or infected material. Confirmation is made by retrograde urethragraphy, micturating cystourethrography and urethroscopy. If the neck is very narrow, it may be difficult or impossible to demonstrate it radiologically. Direct injection of contrast into the diverticulum and sonourethrography may help in outlining the anatomy.
The majority of patients with symptoms referable to the diverticulum, require surgical correction. Endoscopic division of the neck to create a wide communication between the urethra and the diverticulum has also been recommended.
|1||Kurzrock EA, Baskin LS, Cunha GR. Otogeny of the male urethra: Theory of ectodermal differentiation. Differentiation 1999;64:115-22.|
|2||Gupta GK, Srinivas M. Congenital Anterior Urethral Diverticulum in children. Paediat Surg Int 2000;16:565-8.|
|3||Ortilip SA, Gonzalez M, Williams RD. Divericulae of the Male Urethra. J Urol 1980;124:350-5.|