CONGENITAL VALVE
FORMATION AND CYST
Congenital posterior urethral valves are
serious anomalies of the posterior urethra. Thin folds of mucosa originate from
the verumontanum and extend to the sides of the urethra and form a “wind sail”
in the urethra. Urine flow fills the sails and results in chronic obstruction to
urine flow, which then leads to compensatory bladder hypertrophy and eventually
to bilateral hydronephrosis. The condition should be suspected when the following
are observed: difficult urination, enuresis, intractable pyuria, recurrent
urinary tract infection, or evidence of renal insufficiency. The diagnosis can
be difficult to make, because the “valves” are difficult to see (the sails are
floppy) when viewed in a retrograde fashion through cystoscopy. The diagnosis is
best made with a voiding cystourethrogram. With transurethral approaches, the
valve folds can be removed or fulgurated with complete relief of the urinary
obstruction. Renal insufficiency, however, is usually irreversible.
Congenital
cysts of the external genitalia are relatively rare. These cysts, simple or
multiple, are usually situated along the median raphe of the penis at any point
from the frenulum to the scrotum. On palpation they are freely movable, tense,
rounded masses lying just beneath the skin.
Cysts of
the internal genitalia may occur in the Cowper gland within the membranous
urethra and also at the verumontanum (müllerian duct cysts). Cysts occurring in
the verumontanum are vestigial ends of the müllerian ducts (see Plate 1-12) and
can be large and project posteriorly to the prostate and seminal vesicles or
occupy the space between the anterior rectal wall and the posterior bladder and
prostate. Although usually small (few centimeters), they can approximate the
size of a large orange or present as a large abdominal mass. There is usually
communication by a small neck or channel to the utricle at the verumontanum.
Wolffian or ejaculatory duct cysts are usually found laterally along either ejaculatory
duct, unlike midline müllerian duct cysts. Either type of cyst can cause
ejaculatory duct obstruction and present as a low ejaculate volume and
azoospermia. They are quite treatable with transurethral cyst unroofing.
On
occasion, wolffian and müllerian duct cysts may present with other symptoms
beside infertility. A history of intermittent bloody urethral discharge,
dysuria, a sensation of fullness in the rectum, or disturbances in sexual
function that include hematospermia (blood in the semen) or dyspareunia
(painful climax) are not uncommon. The diagnosis is confirmed with transrectal
ultrasound, which may show the cyst in association with dilated seminal
vesicles (>1.5 cm width) or dilated ejaculatory ducts (>2.3 mm wide).
Sophisticated adjunctive techniques such as vasodynamic pressure measurements,
based on the same concept as urodynamic assessment of bladder function, can
confirm physical obstruction of the seminal esicles in cases of partial ejaculatory
duct obstruction.
Other
congenital anomalies (not illustrated) are rare. Congenital urethral
diverticulae are located on the ventral urethra from the triangular ligament to
the glans penis. These diverticulae may, in rare instances, develop to a size
that almost completely obstructs the urethra, similar to cases of acquired
urethral diverticulae resulting from strictures and tumors. Congenital
stricture of the meatus causes dysuria and small ulcerations at the urethral
meatus. Undiscovered meatal stenosis or strictures may lead to voiding
dysfunction, cystitis, and pyelonephritis. Treatment requires antibiotics and
urethral dilation or formal meatotomy. Absence or atresia of the urethra is
very rare but may be associated with other anomalies in which the bladder urine
drains through the urachus into the umbilicus or into the rectum. Congenital
urethrorectal fistula, in which a communication exists between the membranous
urethra and the rectum, is also very rare and is usually associated with
imperforate anus.
