We present here a cohort of seven pediatric patients with retrovesical cysts. Five had antenatally detected cysts behind the bladder or unilaterally abnormal kidneys. In four cases, the presentation was multiple cysts because the ectopic ureter filled the vesicles with urine. In three of them, the cystic outlook of vesicles disappeared after removing the multicystic dysplastic kidney, and in the remaining case, no operation was necessary, as the size of the cystic area was petite, and the multicystic kidney disappeared. In two other cases, the vesicle cyst was single; the other was associated with unilateral renal agenesis (Zinner syndrome) and the other with a small dysplastic ectopic kidney. In the first case, the cyst was drained periurethrally with partial success, and in the other case, the cyst disappeared by itself. In the remaining seventh case, the cyst-like structure was an enlarged prostatic utricle which was treated by dilatation of the orifice to the urethra. The systematic literature review highlighted that in almost two thirds of patients with retrovesical cysts identified, the ipsilateral upper renal tract was also affected.
In boys, congenital retrovesical cysts result either from aberrant development of Wolffian or Müllerian duct cysts [3]. Wolffian duct cysts are located paramedial (seminal vesicle, vas deferens, ejaculatory duct), and Müllerian duct cysts are located in the midline with normal seminal vesicles bilaterally and intact ejaculatory ducts. Acquired seminal vesicle cysts can be associated with inflammation and ejaculatory duct obstruction. Congenital cysts are believed to arise from a malformation of the ejaculatory duct, explaining the scarcity of reports in young children [18].
Seminal vesicle cysts associated with ipsilateral renal agenesis were first described by Zinner, and thus far, over 200 patients have been described [3, 4, 27]. Zinner’s triad is a consequence of a congenital disturbance in the Wolffian duct development and refers to the entity of seminal vesicle cysts, ejaculatory duct obstruction, and ipsilateral renal agenesis [15]. In these cases, it has been proposed that the cysts represent a residue of a dysplastic kidney [18, 28]. In contrast to renal agenesis and Zinner syndrome, most of our patients with retrovesical cysts had MCDK with ectopic ureters draining to the cysts. Previous research has shown that fifteen percent of patients with MCDK have ipsilateral genitourinary tract abnormalities [14]. The close embryologic relationship has been proposed as an explanation for the association between multicystic renal dysplasia and genitourinary malformations during development with both organ systems arising from the Wolffian duct [3, 14, 29].
Most patients with congenital retrovesical cysts are asymptomatic before puberty. Symptomatic presentation is usually in the form of hematuria, dysuria, urgency, frequency, repeated UTI, ejaculatory pain, perineal discomfort, lower abdominal pain, chronic prostatitis, and infertility and begins after puberty [3, 30, 31]. Symptomatic patients are best treated actively. However, surgical cyst excision presents challenges due to anatomical location, with ductus deferens, pelvic nerves, rectum, and ureters posing further reasons for caution. Our patients did not need cyst excision as only one patient presented with cyst-related symptoms, and in his case, patient-reported morbidity was low. In addition, in four cases, the seminal vesicle cysts disappeared after removal or resolution of the dysplastic kidney.
Currently, data on the need for intervention in asymptomatic cases are scarce. Nevertheless, a conservative approach in asymptomatic cases will avoid possible side effects of cyst excision, as long-term follow-up has not been linked to deterioration or worse outcomes [3, 32]. More than 80% of cases reported in children have been asymptomatic without progression during follow-up [3, 5, 17]. In our series, treatment options were dictated by cyst etiology and included heminephrectomy/nephrectomy and transurethral canalization. Most asymptomatic neonates with ectopic ureters were treated by nephroureterectomy of the nonfunctioning kidney because cystic accumulations were, in fact, enlarged vesicles due to the ectopic ureter. In two asymptomatic patients, no intervention was performed since the kidney remnants were tiny and became invisible in follow-up with US. Nowadays, we prefer a conservative approach even if the cysts are larger in the initial evaluation. In the one patient, the cyst was not visible in the US at the latest outpatient clinic; in the other, the cystic accumulation remained very small. In two patients, per urethral drainage was done for patients with Zinner syndrome and a large utricle with partial success.
Our study has limitations. The material is small and heterogeneous and consists mainly of patients with ectopic ureter. The patients with enlarged cystic-looking vesicles underwent nephrectomy of the nonfunctioning kidney despite of not presenting with symptoms. Accordingly, we cannot present the natural history of those cases. In addition, the follow-up time of our patients is relatively short, but we aim to follow our patients up to puberty as recommended [5]. Our study did not include patients with hypospadias or DSD with enlarged utricles, which may also present as retrovesical cysts.
Retrovesical cysts in boys are benign conditions associated with abnormal development of the ureter and kidney. The nature of the cysts is to be diagnosed with ultrasonography and MRI initially. The cases resulting from ectopic ureter were treated with success and without complications by nephroureterectomy. Although symptomatic cases demand distinct treatment strategies based upon whether a dysplastic kidney was involved or not, most patients are asymptomatic during childhood and should be treated conservatively.
