Introduction

Prostatic cystic lesions are rare, with a 0.5%–7.9% prevalence.¹ Mostly asymptomatic, prostatic cystic lesions are chiefly found incidentally during cystoscopy or other diagnostic imaging for unrelated conditions.² As a matter of fact, the noticeable increase in diagnosis of prostatic cystic lesions is attributed to the increased utilization of transrectal ultrasound in urological practice.² The pathogenesis of prostatic cystic lesions can range from benign fluid collection to bacterial in etiology to neoplasia.³ Prostatic cystic lesions can present with symptoms related to obstruction or infection depending largely on the degree of obstruction.⁴ Differential diagnosis can be challenging and can include pure cysts (prostatic cysts, seminal vesical cysts or müllerian duct remnant cysts), posterior urethral diverticuli or an infectious process.⁵ Imaging can help with diagnosis, which may include transrectal ultrasound (TRUS) or magnetic resonance imaging (MRI) of the prostate. Imaging should be individualized based on clinical presentation.³ Specifically, prostatic urethral diverticuli are rare in nature and are usually congenital or secondary to instrumentation, explaining limited literature on the diagnosis and management of prostatic diverticuli. However, the etiology (congenital or secondary) is of no real significance with respect to management.⁵ In this case, we report the presentation, diagnosis and management of prostatic urethral diverticuli as a rare cause of post-void discharge with or without lower urinary symptoms (LUTS).

Case Presentation

A 38-year-old male presented to us with the chief complaint of “seminal discharge” after voiding. Additionally, he reported voiding discomfort at the urethral meatus, continuous suprapubic discomfort and occasional urinary incontinence without awareness. Patient’s medical history was significant for obstructive sleep apnea, neurogenic bladder and Parkinson’s disease. Physical examination was unremarkable. A renal ultrasound was ordered and showed no abnormalities. Prostatic fluid was collected and sent for fluid culture, which was negative for infection. The patient failed multiple combinations of alpha blockers, antimuscarinics, long antibiotic course as well as over-the-counter medications. Given the mixed LUTS at a young age with history of neurological disease, videourodynamic evaluation was performed and revealed a low maximum cystometric capacity and bladder outlet obstruction at the level of the bladder neck. As such, a flexible cystoscopy was prompted, which showed a cystic appearing lesion at the bladder neck, extending to the left prostatic lobe and producing a white, mucoidal discharge into the bladder (figs. 1 and 2). A pelvic MRI was then ordered and showed a nonenhancing 4.3 cm cystic focus in the left paramedian prostatic lobe bulging into the urethra at the level of the internal urethral sphincter and bladder neck. The MRI findings combined with the cystoscopic picture confirmed the diagnosis of prostatic cyst/urethral diverticulum. Accordingly, we performed a semi-transurethral resection of the prostate (semi-TURP) which entailed resection of the proximal portion of the left prostatic lobe where the cystic lesion was located. We avoided complete TURP to minimize the risk of retrograde ejaculation in this young man. After that, the cyst was sent to pathology, confirming its benign nature with no evidence of glandular or stromal hyperplasia, inflammation or malignancy. At 1 month postoperatively, the patient reported resolution of seminal discharge and voiding LUTS.

Figure 1. Cystoscopic image of prostatic cystic lesion.

Figure 2. Cystoscopic image of prostatic cystic lesion.

Discussion

Prostatic cystic lesions as a cause for LUTS and urethral discharge are rare. In this case, urodynamic study was performed, given his mixed LUTS at a young age. The study showed bladder outlet obstruction. This finding, along with refractory urethral discharge, led to the use of cystoscopy, which showed the urethral cyst described above. In order to further delineate the anatomy of the cyst, further imaging using pelvic MRI was done, which confirmed single cyst with no loculation, soft tissue or septation inside. We preferred MRI over TRUS as an imaging modality in this scenario because of the deep location of the cyst into the luminal side of the prostatic urethra and the bladder neck. Furthermore, TRUS could cause more discomfort in this young patient. In addition, MRI is the preferred diagnostic technique in evaluation of neoplasia with other cystic contents (eg central necrosis, hemorrhage with malignant focus or degeneration).³ Transurethral resection of the cyst was the treatment of choice in this case because the simple aspiration of the cyst has a high rate of recurrence.

Figure 3. MRI of the pelvis showing the prostatic cyst (arrow).

Conclusion

Although rare, prostatic cystic lesions should be thought of as one of the differentials in patients with post-void discharge with or without LUTS. Cystoscopy and proper imaging can help establish the diagnosis. Transurethral resection is more effective treatment than the mere cyst aspiration.