Zinner’s syndrome: report of two cases and review of the literature

During the period of utmost sexual or reproductive activity, cysts of the seminal vesicles start to become more apparent, especially between the second to third decades [3]. The seminal vesicle cysts that are less than 5 cm stay asymptomatic and are later discovered a palpable abdominal mass or on digital rectal examination as a palpable fluctuant mass arising from the superior aspect of the prostate gland. Bladder irritation and obstruction could also be related to symptoms of cysts [4, 5]. The most common and frequent symptoms of cysts are abdominal, perineal, and pelvic pain [6–8]. Other pains could be ejaculatory pain, dysuria, hematuria, urinary tract infections, and symptoms of epididymitis and prostatitis. Some of the other symptoms that were reported, but remaining rarely known, are infertility, hemospermia, and enuresis [5]. Cysts that exceed 12 cm are known to be as the “giant” cysts. These could be known through symptoms of bladder and colonic obstruction because of their enormous effect [4]. Few of the prepubertal young men that were examined for epididymitis and chronic urinary tract infections were found with seminal vesicle cysts.

Seminal vesicle cysts may be congenital or acquired [9]. Those that are present since birth, usually develop and become symptomatic during the adulthood. A cyst is created or formed when secretions in the gland owing to insufficient drainage which is lined or related to atresia, which later causes distention of the seminal vesicles [6]. The cysts that were acquired are often bilateral and are discovered after a history of chronic prostatitis or even a prostate surgery [3]. The relation between seminal vesicle cysts and ipsilateral renal agenesis can be explained by their common embryological origin. The ureteral bud originates from the dorsal aspect of the distal mesonephric duct and extends in a dorsocranial fashion to meet and induce differentiation of the metanephric blastema, which will form the adult definitive kidney. The mesonephric duct differentiates into the appendix of the epididymis, paradidymis, epididymis, vas deferens, ejaculatory duct, seminal vesicle, and hemitrigone [10, 11].

The kidney’s development all relies on the stimulation of the ureteric bud and mesonephric duct. The failure of the ipsilateral kidney, ureter, hemitrigone, and seminal vesicle are usually derived from the malfunction of the mesonephric duct. This will lead to ipsiltaeral renal agenesis or dyplasia. If the ureteral bud arises in a more cephalic position off the mesonephric duct, delayed absorption of the caudal mesonephric duct will result in the distal ureteral bud emptying into mesonephric duct derivatives, including the vas deferens, seminal vesicle, ejaculatory duct, or into the bladder neck and urethra [12]. Ectopic ureters entering seminal vesicle cysts associated with ipsilateral renal agenesis are uncommon; however, they have been reported and may be complicated by reflux and obstruction [7]. All this explains that the seminal vesicle cyst associated with agenesis or dysplasia of the ipsilateral kidney is rare. Their frequency is estimated, according to a Chinese study of 280,000 children at 0.00035 % [13].

For the evaluation and discrimination of pelvic cystic masses, there were many imaging techniques are used. Excretory urography can show ipsilateral renal dysgenesis and an abnormal appearance of the collecting system [9]; however an extrinsic smooth-walled filling defect in the bladder that is suggestive of a seminal vesicle cyst may not be visualized. The advanced technology known as the sonographic can determine cystic nature of the pelvic masses, the size and location, and define intraprostatic anatomy [9, 14, 15]. These latest discoveries or findings are an anechoic pelvic mass with a thick and irregular and occasional wall. Sometimes the mass may also consist of internal debris related to an early infection [9]. Reported findings with vasovesiculography include dilatation, mass effect with deformity of the seminal vesicle, ejaculatory duct stenosis, and reflux of contrast material in an ipsilateral ectopic ureter.

CT can accurately show renal anomalies and define pelvic anatomy. Reported findings have been variable ranging from a cystic pelvic mass with a thick irregular wall to a solid mass and apparent enlargement of the ipsilateral seminal vesicle. Other reported findings include a well-defined low-attenuation retrovesicular mass arising from the seminal vesicle, cephalic to the prostate gland, with associated renal anomalies [9].

The multiplanar ability of MR imaging to define abdominal and pelvic anatomy and to differentiate cystic malformations of the pelvis make it the ideal imaging study, allowing prompt diagnosis. In our study, the two patients that had symptoms of dysuria and irregular perineal pain were because of the late or missed diagnosis that was supposed to be done earlier. The usual appearance of a seminal vesicle cyst is that of cyst located elsewhere in the body, showing low T1-weighted and high T2-weighted signal intensity. However, seminal vesicle cysts may show increased T1-weighted and T2-weighted signal intensity, thought to reflect increased concentration of proteinaceous material or hemorrhage [16]. Some undergo surgery for these symptoms but it all depends in the size of the cyst. MR imaging are used to determine the approximate location where the cyst is located before any excision is done.

Only the symptomatic forms of treatment are justifiable. This treatment is surgical: excision of the cyst. This surgical approach may be made by trans-vesical way, extra bladder or laparoscopically [11, 17]. According to Williams, the way transcoccyx should be a last resort because exposure to the risk of rectal injury and impotence. Using the transperineal route is a fascinating way to cure the cyst, but it does not allow treatment of the associated anomalies in the same time [11, 18]. An alternative to other surgical procedures or approaches can be done using laparoscopy. But this technique has a limit when some of the surgeries require a ureteral reimplantation. Other approaches have also been proposed: transrectal. In case of recurrence after aspiration, some authors recommend to redraw the cyst and then to inject a sclerosing agent [19].