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URETHRAL ANOMALIES VERUMONTANUM DISORDERS


URETHRAL ANOMALIES, VERUMONTANUM DISORDERS
Diverticula are outpouchings of the urethral lumen that occur in both the anterior and posterior urethra. They may be congenital or acquired. The congenital variety, usually located in the penile urethra, is more frequent. Diverticula are further divided into true and false (pseudodiverticula) forms. The true diverticulum is generally congenital in origin and has a mucous membrane lining continuous with that of the urethra, whereas the wall of the false type is initially an unlined pouch as a result of a neoplastic or inflammatory process. Destruction of the mucosal lining of a true diverticulum by inflammation may render the two types indistinguishable. A false, acquired diverticulum may become epithelialized following surgical drainage of a periurethral abscess and may be interpreted as a true variety. Acquired diverticula are frequently observed in spinal cord injury patients who develop painless, undetected periurethral abscesses from chronic urethral catheters. These are “false” at the onset but appear “true” after epithelialization. Acquired pseudodiverticula are frequently found in the posterior urethra following instrumental trauma, whereas congenital diverticula are almost always located on the ventral wall of the anterior urethra.

URETHRAL ANOMALIES VERUMONTANUM DISORDERS

Difficult urination (stranguria) or recurrent urinary tract infections are the most common presenting symptom. In addition, a common history is that during micturition, a mass appears in the perineum, scrotum, or under the penis that slowly disappears with dribbling of urine from the urethra. The condition is suspected by observation and palpation of the diverticular mass and the diagnosis is confirmed by urethroscopy and antegrade or retrograde urethrography. Diverticula are rarely asymptomatic and are best treated by complete excision and reconstruction of the urethral channel.
The accessory or duplicated urethra is very rare and has an unknown embryologic origin. They end blindly, generally at a depth of 3 to 10 mm (incomplete form, Effman Type I), but can be much longer and connect with the urinary tract (complete form, Effman Type II). They can communicate with the true, orthotopic urethra and for the most part are located ventral (hypospadiac) to the true urethral channel. When found dorsal to the true urethra, they are termed epispadiac duplicated urethrae. The most common type of urethral duplication is the Y type, in which a perineal meatus accompanies the usual orthotopic penile meatus. Retention of inflammatory exudates within these accessory structures can lead to recurrent abscess formation and intermittent purulent discharge. Infected anomalous tracts may require complete marsupialization or excision to eradicate the chronic inflammation.
Disorders of the verumontanum can be found in all age groups. The verumontanum represents the fusion of the terminal müllerian ducts (see Plate 2-12) and is located in the posterior urethral floor proximal to the external urethral sphincter. The only known function of this structure is to direct the semen during ejaculation. Congenital hypertrophy of the verumontanum is probably caused by maternal estrogens. It may be quite enlarged in young children and may nearly obstruct the prostatic urethra. Obstructive urinary symptoms such as stranguria and urinary frequency occur, until over- flow incontinence develops. This form of incontinence in this age group can often be confused with benign enuresis. When severe, the back pressure induced by this obstruction on the upper urinary tract results in renal damage, especially if urinary tract infection is present. Surgical removal of the histologically normal but enlarged verumontanum by transurethral resection is usually curative but renal damage may persist.
Verumontanitis, or inflammation of the verumontanum, is usually due to underlying inflammation from chronic prostatitis, urethritis, or seminal vesiculitis. Visible changes include simple vascular engorgement or congestion, with or without edema. Chronic cases assume a granular and cystic appearance. Verumontanitis in adults can provoke abnormal sexual symptoms, such as pain with ejaculation or hematospermia, and can cause urinary symptoms such as frequency and urgency. The ejaculatory ducts may be obstructed, leading to seminal vesicle dilation and pain radiating to the low back, perineum, scrotum, and rectum. The diagnosis is generally made by urethroscopy and treatment is directed at the underlying obstructive or inflammatory condition.