Severe lower urinary tract symptoms due to anteriorly located midline prostatic cyst arising from the bladder neck in a young male: case report

ABSTRACT CONTEXT: Prostatic cysts are uncommon. These cysts are usually asymptomatic and are diagnosed incidentally during ultrasonographic examination. On rare occasions, they may cause drastic symptoms. CASE REPORT: We report on a case of severely symptomatic anteriorly located prostatic cyst arising from the bladder neck in a 30-year-old man presenting with lower urinary tract symptoms, without clinical evidence of benign prostatic hyperplasia. Transrectal ultrasonography (TRUS), computed tomography (CT) and cystourethroscopy demonstrated a projecting prostatic cyst that occupied the bladder neck at the precise twelve o’clock position. It was acting as a ball-valve, such that it obstructed the bladder outlet. Transurethral unroofing of the cyst was performed and the patient’s obstructive symptoms were successfully resolved. Histopathological examination indicated a retention cyst. CONCLUSIONS: It should be borne in mind that midline prostate cysts can be a reason for bladder outlet obstruction in a young male. Such patients may have tremendous improvement in symptoms through transurethral unroofing of the cyst wall.


INTRODUCTION
Over recent years, the widespread availability of transrectal ultrasound (TRUS), computed tomography (CT) and magnetic resonance imaging (MRI) has led to increased frequency of diagnoses of incidental prostatic cysts.The majority of prostatic cysts are asymptomatic and originate in the posterior area of the prostate, such as in the Müllerian ducts and the utricle, as an embryological remnant; these cysts are observed in 0.5% to 7.9% of patients. 1,2However, these improved imaging techniques have increased the incidental determination of midline prostatic cysts (MPCs) in adult males, and the frequency of these findings is currently estimated to be 5-14%. 33][4] Prostatic retention cysts rarely become symptomatic, but they may cause symptoms when the cyst enlarges to more than 3 cm.[4][5] We report on the case of a severely symptomatic, anteriorly located prostatic cyst arising from the bladder neck in a 30-year-old man who presented with lower urinary tract symptoms (LUTS), without any clinical evidence of benign prostatic hyperplasia or any endoscopic management.To our knowledge, symptomatic MPCs are generally located posteriorly and are rare.8][9][10][11][12]

CASE REPORT
A 30-year-old healthy man came to our outpatient clinic with a two-year history of severe LUTS, including frequent voiding, hesitancy, weak urinary stream and the sensation of residual urine.Despite alpha blocker drug treatment, his symptoms had worsened.His medical history was not significant in terms of previous urethral catheterization, urinary tract infection, pelvic/perineal trauma or neurological deficit.He had two children and did not have any ejaculatory complaints or infertility.
His International Prostate Symptom Score (IPSS) was 20, and his quality-of-life (QoL) score was 5. Digital rectal examination revealed a normal firm and nontender prostate without palpable nodules.A routine urine examination was normal and the culture was sterile.The urine cytology was not suggestive of malignancy, the serum prostatic specific antigen (PSA) level was 0.82 ng/ml (the reference value for PSA for the age range of 30-40 years is 0-2 ng/ml), and routine biochemical laboratory examinations were within normal limits.Uroflowmetry (Figure 1) demonstrated a peak flow rate (Qmax) of 7.6 ml/sec with a voided volume of 230 ml, and the postvoid residual urine volume was 107 ml (the reference values are voided volume > 150 ml and Qmax >15 ml/s).TRUS showed an anteriorly positioned prostatic cyst arising from the bladder neck and obstructing the bladder outlet.The cyst diameter was approximately 13 x 10 mm, inside a prostate with a volume of 22 ml.CT urography was performed to identify the origin of the cystic lesion and to rule out ectopic ureter or ureterocele (Figure 2).
The patient then underwent cystourethroscopy examination under general anesthesia.This showed that the posterior wall of the prostatic urethra was normal and that there was cystic hemispherical bulging based on the anterior portion of the prostate.The bulge was located on the bladder neck at precisely twelve o' clock and was entirely compressing the bladder outlet.
It was acting like a ball-valve, without lateral lobe hyperplasia (Figure 3).Moderate trabeculation due to gross back pressure change was also noted in the bladder.Transurethral marsupialization of the prostatic cyst to release the anatomical obstruction was performed, and milky fluid was expelled during the unroofing procedure.
A urethral catheter was left in place for two days, and the patient was then discharged.Histopathological examination revealed that the cyst wall was lined with benign flattened prostatic glandular epithelium without any preneoplastic change, which was consistent with the diagnosis of a prostatic retention cyst.At a return visit in the third postoperative month, a subjective dramatic improvement in symptoms was noted.
IPSS was 5 and QoL was 2 at three months after the operation.
Uroflowmetry showed an increased Qmax (18 ml/sec with a voided volume of 300 ml) and no residual urine.Furthermore, the patient had no symptoms suggestive of erectile dysfunction or ejaculation disorders.

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Severe lower urinary tract symptoms due to anteriorly located midline prostatic cyst arising from the bladder neck in a young male: case report Sao Paulo Med J. of cases. 1 It has been reported that MPCs were observed in 7.6% of healthy men and 5% of symptomatic outpatients. 2Over recent years, new imaging techniques such as TRUS, CT and MRI have increased the incidental determination of MPCs in adult males, and their frequency is currently estimated to be 5-14%. 3,13,14wever, the majority of prostatic cysts are asymptomatic.They can be categorized as symptomatic when the cyst's presence is accompanied by infection or if its size and anatomical relationships affect the adjacent structures, which are most often located laterally. 14An analysis on 34 patients with symptomatic prostatic cysts by Tambo et al. 7 revealed that 40% of the patients suffered from obstructive urinary symptoms, 33% from urinary retention, 9% from urodynia and 6% from infertility.
In 2009, Galosi et al. 1  This finding may be useful for classifying various kinds of midline cysts of the prostate.However, in practice, this classification is not  16,17 Moreover, there are no sperm cells in the fluid obtained from prostatic retention cysts, and they usually do not cause symptoms.However, on rare occasions, they may cause obstructive symptoms if located close to the bladder neck, as in the case of our patient. 16,17though approximately 35 patients with symptomatic prostatic cysts have been reported, there are only seven published reports on anteriorly located MPCs. 11Furthermore, to the best of our knowledge, only seven such cases of MPC of the bladder neck have been reported in the literature, as in our case.Also, this is the first case of an anteriorly located MPC of the bladder neck found in Turkey. 7,11ltiple therapeutic options have been described for management of symptomatic prostatic cysts, including transrectal aspiration with or without sclerotherapy, marsupialization with a transurethral technique and open surgery. 7,18,19Although recurrences of cysts that were incompletely excised during open surgery have been reported, recurrence-free results have been reported for medial prostatic cysts treated with the transurethral technique. 2,6Chang et al. 10 previously reported successful results from transurethral resection of an MPC presenting with LUTS.Zhang et al. 20 also recommended transurethral unroofing of small prostatic cysts (< 2 cm x 2 cm) that are close to the bladder cavity or urethra, because of the simplicity of the technique, the low risk of complications and the shorter convalescence period.
We searched for similar cases in different databases (PubMed, Embase and LILACS databases) using the terms: "prostatic cyst" AND "lower urinary tract symptoms" AND "midline" (Table 1).
We found that few cases have been published.
Our patient was suffering from obstructive voiding problems rather than irritative symptoms, and transurethral unroofing of the prostatic cyst, which was located anteriorly in the midline position, provided satisfactory results for his complaints.In this case, standard transurethral resection of the prostate was avoided in order to prevent antegrade ejaculation and erectile dysfunction, in the absence of the lateral lobe of prostatic hyperplasia.

CONCLUSION
Although symptomatic anteriorly located MPCs of the bladder neck, as described in the case presented here, are uncommon, they should be borne in mind in the differential diagnosis of obstructive voiding symptoms, especially in young patients and patients who do not respond to medical therapy such as use of alpha-blockers.Transurethral unroofing of the cyst may provide safe treatment with successful and satisfactory results in selected cases.

Figure 2 .
Figure 2. Sagittal (A) and axial (B) computed tomography urography images showing low-density small nodular lesion in the bladder neck that represents the anteriorly positioned midline prostatic cyst (arrow).

Figure 3 .D
Figure 3. (A) and (B): anteriorly positioned midline prostatic cyst obstructing the bladder neck with action like a ball-valve; (C) and (D): transurethral unroofing of the cyst.
classified prostatic cysts into six distinct types based on TRUS and pathological correlation: isolated medial cysts, cysts of the ejaculatory duct, simple or multiple parenchymal cysts, complicated cysts (infectious or hemorrhagic), cystic tumors and secondary cysts relating to parasitic disease.MPCs are less common and are generally located posteriorly.They have traditionally been classified as Müllerian duct cysts and as enlarged prostatic utricles (mega-utricles), ejaculatory ducts, seminal vesicles and prostatic retention cysts.15,16Furuya et al.17 classified MPCs, with or without the presence of sperm in the fluid content, using concomitant TRUS-guided opacification and dye injection.If there is communication with the seminal tract, then sperm can be found in the fluid content.They further classified MPCs into four categories: Type 1 MPC with no communication into the urethra (traditional prostatic utricle cyst); Type 2a MPC with no communication into the urethra [cystic dilatation of prostatic utricle (CDU)]; Type 2b CDU in communication with the seminal tract; and Type 3 cystic dilatation of the ejaculatory duct.They also found that the location, shape and volume of the MPC and the PSA level of the MPC fluid did not influence the classification.18

Table 1 .
Search of the literature in medical databases for case reports on "Severe lower urinary tract symptoms due to anteriorly located midline prostatic cyst arising from the bladder neck in a young male".The search was conducted onApril 12, 2016