Background

Prostatic utricle (PU) is a remnant of mullerian duct. Persistent müllerian duct in males may result in an enlarged PU (prostatic utricule) or a müllerian duct cyst [1]. Prostatic utricle arises from the prostate in the midline at proximal verumontanum level in between the ejaculatory ducts (Fig. 1). Although most of them are symptomatic, asymptomatic cases are also reported [2]. The pathological presentations of PU are variable [3]. Association of PU with severe hypospadias and intersex is high as 14–27.5% [1, 4, 5], approximately 11–14% are associated with proximal hypospadias [6, 7]. Thus, the literature shows that the incidence of PU increases with the severity of hypospadias. About 29% of children may present with clinical symptoms in childhood due to increase in the size of PU, recurrent UTI [8], stones, epidydimo orchitis, dysuria and psedoincontinence due to trapping of urine in the pouch [2, 9], cystoscopy, micturating cystourethrogram (MCUG), and ultrasonography are diagnostic [10, 11].

Fig. 1
figure 1

Anatomy of posterior urethra showing the location of prostatic utricle (PU) opening

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Symptomatic and enlarged PU should be actively treated [9]. The treatment is intended to relieve symptoms, preserve fertility, and prevent neoplastic degeneration [12]. The suitable approach should be based on the age, symptoms, and size and location of the utricle [9]. Several surgical approaches have been used in the past for the excision of PU. Various treatment approaches include abdominal transperitoneal, perineal or combined abdomino perineal, anterior or posterior sagittal transrectal, rectum-retraction, suprapubic extravesical, and transvesical transtrigonal approaches [2, 9, 13, 14]. Being such a rare anomaly, and given its challenging anatomical location, there has been no consensus about the best surgical approach to excise a PU [10]. Further, surgical management of PU remains challenging due to the close proximity of the lesions to ejaculatory ducts, vas deference, pelvic nerves, ureters, and rectum [1]. The complications associated with surgical approaches include urethral injury, rectal injury, infertility, impotence, and fecal incontinence [7].

The objective of this retrospective study was to highlight the importance of diagnosis of PU through various clinical presentations and varying surgical approaches to treat a symptomatic PU in children.

Methods

This retrospective study was conducted at the Department of Pediatric Surgery, Tertiary care Medical College Attached Hospital, India. Seven cases (newborn to 11 years of age) of symptomatic PU were diagnosed and managed over a period of 5 years. Informed consent was obtained from all parents/guardians. Ethical committee (EC) clearance was obtained from the institute.

Inclusion criteria was symptomatic patients diagnosed to have PU, and asymptomatic patients were excluded.

All cases were diagnosed with PU during evaluation of various urinary symptoms. The diagnosis was made on the basis of clinical presentations, cystoscopy, MCUG, and USG. Cystoscopy was used for diagnosis in 4 cases (case n° 2, 4, 5, and 7), MCUG in 6 cases (case n° 1, 2, 3, 4, 6, and 7), and USG in 1 case (case n° 1). The size of the PU was graded as per Ikoma and colleagues classification [4] (Fig. 2).

Fig. 2
figure 2

Classification of enlarged prostatic utricle (PU). a Grade 0 opening located at posterior urethra, does not extend beyond the verumontenum. b Grade I Larger than grade 0, but does not reach the bladder neck. c Grade II Enlarged PU extends over the bladder neck

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Grade 0: opening located on the posterior urethra but the utricle does not extend over the verumontanum;

Grade I: larger than grade 0 but it does not reach bladder neck;

Grade II: more enlarged and its dome extends over the bladder neck (PU opens into the central area of the verumontanum in the prostatic urethra in grades 0, I, and II);

Grade III: opening is situated in the bulbous urethra just distal to the external sphincter (in rare cases).

Various treatment modalities were used depending on clinical presentation, cystoscopy, MCUG, and USG findings. The management protocol which is explained in Fig. 3 was followed for our cases. The definitive treatment was individualized as mentioned in Table 1. Case 1 was the newborn baby with urinary retention diagnosed to have intra-abdominal cystic mass underwent diagnostic laparoscopy, due to technical difficulties it was converted to open surgery. In this child, laparotomy was done; after aspirating the cyst, it was dissected behind the bladder neck as low as possible and neck of the cyst was transfixed with absorbable 4–0 suture, and excision of the PU cyst was done. Case 2 was a child with DSD who underwent laparoscopically assisted excision of PU through midline perineal incision; urethra was repaired over the catheter using absorbable 4–0 suture. Cases 4 and 7 underwent perineal excision of PU through a midline perineal incision; the PU neck was approached and transfixed with absorbable 4–0 suture. The rest of the PU was dissected and excised. Cases 3, 5, and 6 underwent cystoscopic fulguration of the PU opening and the mucosa using bugbee electrode, since the opening was wide enough to insert 8 Fr cystoscope.

Fig. 3
figure 3

Approach to symptomatic prostatic utricle (PU)

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Table 1 Clinical presentations and surgical approaches to treat a symptomatic prostatic utricle
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Results

A total of 7 cases of symptomatic PU (newborn to 11 years of age with mean age of 3.2 years) were encountered over period of 5 years. Variable clinical presentations were encountered (Table 1). One case (case n° 1) was diagnosed in newborn period presented with antenatally detected abdominal mass with hydronephrosis with postnatal urinary retention. MCUG in this case showed a huge cystic mass arising from junction of bulbar and prostatic urethra. The abdominal cyst reduced in size after perurethral catheterization. Cystoscopy confirmed the opening of the cyst in the proximal bulbar urethra. Five cases (case n° 2, 3, 4, 5, and 7) were associated with perineal or penoscrotal hypospadias and severe chordee, recurrent UTI, and severe dysuria. Two cases (case n° 4 and 6) had recurrent epididymo-orchitis. Figure 4 depicts MCUG of a child (case 4) with recurrent epididymo-orchitis showing grade 2 PU and post-void film showing retention of dye in PU pouch. Figure 2 shows the classification of PU as per the grades observed. Cystoscopy was done in all patients to confirm the position of the opening.

Fig. 4
figure 4

Micturating cystourethrogram (MCUG) showing the prostatic utricle (PU) and retained dye in the pouch in post void film

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Per urethral catheters were removed after 5 to 7 days of procedure. All 7 cases were followed up for the period of 1 to 2 years. Except one child who initially had recurrent epididymo-orchitis, all patients have remained well on regular follow-up. All cases made an uneventful recovery from surgery. None of them experienced further episodes of urinary complaints to date. Patients with associated hypospadias eventually underwent staged repair, after 1 year of symptom-free follow-up.

Discussion

Prostatic utricle is a rudimentary structure in the posterior urethra of males. It is an embryological remnant, 4- to 6-mm long opening between two ejaculatory ducts on verumontanum. It denotes the caudal end of fused müllerian duct, conforming to vaginal and cervical portion of the duct [15]. The utricle abnormalities occur due to an inadequate regression of müllerian duct or inadequate urogenital sinus closure caused by inappropriate production or sensitivity to testosterone or müllerian inhibiting substance leading to PU among various stages of hypospadias, intersex, and cryptorchidism [15]. It may also occur due to a transient decline in the fetal testicular utility during the phase of urethral formation of fetal life [6]. The utricular pouch is described as vagina musculina in cases with intersex wherein female internal organs like rudimentary uterus and fallopian tube are also present [13]. A PU is a relatively common observation in male hypospadias and its frequency seems to increase with the severity of the disorder [16, 17]. The distinction diagnosis may include severe hypospadias with or without accompanying intersex, male pseudohermaphroditism, mixed gonadal dysgenesis, or true hermaphroditism [5]. Symptomatic PU with normal external genitalia is still more challenging to diagnose due to irregularity in the presenting symptoms [9]. The management of such remnants requires a skill for complete excision and preserving fertility [12].

The clinical symptoms of PU includes urinary tract irritative symptoms, post-void dribbling, urethral discharge, stones in the utricle pouch, recurrent UTIs, recurrent epididymo-orchitis, pseudo-incontinence, and rarely outlet obstruction or malignancy in PU [2, 9, 12]. In our study, 5 cases were with severe hypospadias, chordee, recurrent UTI, and dysuria, 2 cases were with recurrent epididymo-orchitis, and 1 case was with antenatally detected abdominal mass with hydronephrosis with postnatal urinary retention are observed.

Cystoscopy and MCUG are gold standard for diagnosis that helps to plan the treatment in such cases [11, 18]. Cystoscopy facilitates complete excision of the PU [10]. The MCUG demonstrates the lower urinary tract and helps to detect vesicoureteral reflux (VUR), bladder pathology, congenital, or acquired anomalies of bladder [19]. The diagnosis can also be made using USG [11]. It may add complementary information about the morphology of the PU and it is reported to be noninvasive and painless [16]. In our study, cystoscopy, MCUG and USG were diagnostic for PU in all the 7 cases. Sometimes during hypospadias repair inability to introduce catheter into the bladder reveals the presence of PU. In such cases, PU should be treated first and hypospadias repair should be done at a later stage. Recurrent episodes of epididymo-orchitis due to enlarged PU are attributed to the obstruction of ejaculatory ducts which open on either side of the verumontanum (Fig. 1).

The PU is classified into four types from the perspective of size and location of the opening of the utricle. Ikoma and colleagues devised grading system (grade 0, grade I, grade II, and grade III) for PU with hypospadias. The higher grades (grade II and grade III) are seen more often in patients with severe hypospadias [4]. In our study, 2 cases had grade 3 PU, 1 case had grade 1 PU, and 4 cases had grade 2 PU. This confirmed a direct relationship between the degree of hypospadias and the increasing size of the PU.

Various approaches have been described for surgical intervention in PUs [12]. A flowchart proposing management protocol for symptomatic PU cases is presented in Fig. 3. Prostatic utricle have traditionally been excised via the open approach or laparoscopically [12, 20]. Other surgical approaches include abdominal extravesical, transtrigonal, suprapubic, extravesical transperineal, parasacral, retropubic, transanorectal anterior or posterior sagittal approach [14], transurethral deroofing, and endoscopic fulguration. However, these approaches can be challenging and involve complications. All these approaches require extensive dissection, often requiring two stages and result in poor exposure. Most common complication are incontinence, infections, and impotence secondary to injury to pelvic nerves [6, 7, 12, 15].

Laparoscopic approach for the excision of PU has been successful in children [21, 22]. Schuhrke and Kaplan described endoscopic transurethral cyst catheterization and aspiration, cyst orifice dilatation, or incision and deroofing, and reported that it is well suited to this problem [23]. Ahmad and Palmer reported successful transperineal cyst aspiration and sclerotherapy with tetracycline under transracial ultra sound guidance [24]. In our study, one case underwent laparoscopy-assisted perineal excision of the PU and reaffirms the benefits of laparoscopy in these deep pelvic anomalies. Three cases successfully underwent cystoscopic cauterization. One case underwent laparotomy and excision of the PU cyst while two cases underwent perineal approach for excision of PU. The removal of the utricle with our approaches ended the urinary symptoms. All 7 cases were followed up for the period of 1 to 2 years. Except one child who initially had recurrent epididymo-orchitis, who eventually became asymptomatic with conservative management. All cases have been asymptomatic.

The clinical presentations and various surgical approaches used to treat PU in children in various clinical studies from other researchers are summarized in Table 2.

Table 2 Various studies reporting clinical presentations and treatment approaches for treatment of prostatic utricle
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Conclusion

Prostatic utricle should be considered as one of the differential diagnosis in children with recurrent urinary complaints as it assures early detection and management, more so with severe hypospadias, although isolated PU are also known. MCUG and cystoscopy are hence recommended in all cases of severe hypospadias as preoperative workup before planning hypospadias repair. The ideal surgical approach requires accurate diagnosis of the location of PU. Missed or delayed diagnosis of PU can lead to fatal consequences like renal failure; hence, it is important to diagnose PU in time and treat appropriately.