Pediatric Surgery, AlSadik Hospital, Qatif, Saudi Arabia
The prostatic utricle is a small, epithelium-lined diverticulum of the prostatic urethra.
Utricle is derived from the Latin word “pouch,” which forms a cul-de-sac. The prostatic utricle (pouch of the prostate) is a small diverticulum (6 mm long) in the prostatic urethra (Fig. 20.1).
A micturating cystogram showing a large utricular cyst
It is located in the verumontanum (seminal colliculus) between the two openings of the ejaculatory ducts and extends backward and slightly upward for a very short distance within the medial lobe of the prostate.
It is also known as the vagina masculina or vesicula prostatica.
It is a normal anatomic variant representing the remnant of the fused caudal ends of the Müllerian ducts. This origin is occasionally disputed.
It is considered to represent the male homologue of the female uterus and vagina.
In 1905, Robert William Taylor stated the function of the prostatic utricle thusly: “In coitus it so contracts that it draws upon the openings of the ejaculatory ducts, and thus renders them so patulous that the semen readily passes through.”
Utricle cysts always arise from the level of the verumontanum and are always in the midline.
The cyst typically lies between the bladder and the rectum and, thus, is palpable on per rectal exam in 50 % of the cases.
They are variable in size but are usually small in size (commonly <10 mm). They can however grow to reach a large size.
Morphologically, prostatic utricle cyst appears as a small, single, smooth, unilocular cyst of variable size.
The cyst lining can be:
Squamous or transitional type
Prostatic utricle cyst is usually seen during the first to second decades of life, with a mean age range of 26 years.
There is an association between utricular cysts and:
Renal agenesis/dysgenesis (10–25 %)
Hypospadias (25 %) (Figs. 20.2 and 20.3)
Figs. 20.2 and 20.3
Clinical photographs showing severe hypospadias. This is known to be associated with utricular cyst. The increasing severity of the hypospadias correlates with increasing size of the utricle
Prune-belly syndrome (Fig. 20.4)
A clinical photograph showing Prune belly syndrome which is known to be associated with utricular cyst
Hypospadias is considered the most commonly associated malformation with the prostatic utricle (14–47 %), and the increasing severity of the hypospadias correlates with increasing size of the utricle (Figs. 20.2 and 20.3).
Normally, the prostatic utricle distends with urine during voiding and then passively drains.
Poor emptying leads to urine retention and stasis and this leads to complications including:
Recurrent urinary tract infection
Post voiding urine drippling
Stone formation within the utricle cyst
Malignant transformation (e.g. clear cell carcinoma, or squamous cell carcinoma) with a reported prevalence as high as 3 %.
Utricular cyst is rare but along with its rarity, it presents a challenge in its diagnosis and proper management. Awareness of this is important.
Persistence or untreated prostatic cyst could be a cause of infertility.
The differential diagnoses include mullerian duct cysts, bladder diverticulum, cystic teratoma, seminal vesicle cyst, epididymal cyst and Wolffian duct cyst.
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Embryologically, in the male fetus the Mullerian ducts regress under the influence of anti-Mullerian hormone (Mullerian inhibiting substance).
This is a glycoprotein secreted by the Sertoli cells of the fetal testes at eight gestational weeks.
Persistence of the Mullerian ducts as result of failure of synthesis or action of Mullerian inhibitory substance results in persistent Mullerian duct syndrome.
This is characterized by the presence of uterine tissue and fallopian tubes in a phenotypic and genotypic male.
Utricular cysts are thought to result from incomplete regression of the Mullerian ducts or incomplete androgen-mediated closure of the urogenital sinus caused by an error in the production or sensitivity to local testosterone or anti-Mullerian hormone.
These cysts are differentiated anatomically from Mullerian duct cysts.
Always in the midline
They present during the first to second decade of life
They communicate with the urethra
They have a tubular or vesicular shape
The majority are seen in younger patients
They have an association with unilateral/bilateral renal agenesis, and hypospadias
They can be visualized with a micturating cystourethrogram or a retrograde urethrogram.
Mullerian duct cysts:
Usually seen above the prostate
They are seen in the older age group ranging from 2 to 75 years
Mullerian duct cysts generally do not communicate with the urethra
They cannot be visualized with a micturating cystourethrogram or a retrograde urethrogram.
It is proposed that these cysts originate due to failure of fusion of Mullerian duct resulting from deficient Mullerian inhibitory factor.
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