Prostatic-type polyp located in the bladder of an adolescent: A case report and overview

Abstract

Prostatic-type polyps are uncommon lesions in the urinary tract. They are sometimes found in the lower urinary tract, particularly on the posterior urethra, but are rarely found in the bladder. We report a case of 15-year-old boy who presented with dysuria. Routine ultrasonography showed a mass in the bladder arising near the internal orifice of urethra. Further inspection with cystoscopy followed by transurethral resection and pathology confirmed the lesion to be a prostatic-type polyp. An overview of other similar case studies showed that the pathogenesis of this condition is controversial, haematuria and dysuria are common clinical symptoms and endoscopic transurethral resection is the best treatment option. Since the polyp is benign, recurrence and progression of this disorder is unlikely to occur.

Introduction

Prostatic-type epithelial polyps are unusual, benign lesions found in the urinary tract system. ¹ The lesions were first described approximately 100 years ago ² and are known by several synonyms including aberrant prostatic tissue, adenomatous polyps, benign villous polyps of the urethra and papillary adenoma of prostatic urethra. ³ Most commonly, the polyps grow on the posterior urethra and are seldomly found in the bladder. ⁴ We report here on a case of a 15-year-old adolescent boy who presented with dysuria. Imaging and pathology studies confirmed the presence of a polypoid lesion in the bladder arising at the internal orifice of urethra. The lesion was confirmed to be a prostatic-type polyp. Other similar case reports were identified and commonalities discussed.

Case report

The patient was a 15-year-old adolescent boy who presented to our institution with a six-month history of dysuria. The patient complained of voiding difficulties which had progressively worsened and medical history showed no obvious causes. Initially, the patient's main symptoms were sudden interruption on urination and prolonged micturition time and no haematuria or dysuria. The patient underwent routine examinations at the hospital. Ultrasonography showed the presence of a mass in the bladder arising near the internal orifice of urethra, 1.4 cm×1.3 cm in size with clearly defined boundaries. Doppler ultrasound delineated the blood flow inside the tumour. Cystoscopy confirmed a large mass at the bladder neck at the 1 o’clock position attached with a broad pedicle (Figure 1).

Figure 1.

Cystoscopy results showed a spherical mass with a board pedicle at the bladder neck.

The patient had no history of smoking or previous exposure to toxic chemicals or drugs and no family history of cancer. In addition, his physical examination was unremarkable. Transurethral resection was performed successfully; there were no post-operative complications and the voiding dysfunction abated. Pathology of the mass showed polypoidal lesions of a papillary structure covering most of the prostatic ductal epithelium (Figure 2a). Immunohistochemical staining was positive for prostate specific antigen (PSA) and confirmed that the mass originated from the prostate and not from the bladder (Figure 2b).

Figure 2.

(a) Histological examination showing fibrovascular core covered by a prostatic type epithelium (HE stain, 100X) (b) Positive staining of the epithelium for prostate specific antigen (HE stain, 100X).

The patient attends routine follow-up every three months and the most recent examinations show that he is recurrence-free, 18 months post-surgery. Written informed consent was obtained from the patient before publication of his medical record.

Discussion

Although the morphological and histopathological features of prostatic-type polyps have been defined, ⁵ the histogenesis remains controversial and may vary according to the site of the polyp. ⁶ Several unsubstantiated hypotheses have been proposed to explain their development and include, activation of embryonal cell nests, excessive hyperplasia of prostatic-type epithelium and metaplasia. ³ While some reports suggest that the condition affects all age groups,^1,4 others have found that the lesions are common in elderly patients with benign prostatic hyperplasia. ⁶

Based on the size and location of the lesion, this disease may present a variety of clinical symptoms. From a review of 22 other case reports (Table 1), the most common site of prostatic-type polyps in the bladder was the trigone and the most frequent presenting symptoms were haematuria and dysuria^6–27 Interestingly, in several cases, the condition was asymptomatic. Radiologic imaging and cystoscopy were commonly used to detect the disease and the lesion usually presented as an isoechoic mass on ultrasound. ²⁶ On cystoscopy, the polyp may present as a villous, papillary or frond-like mass which can be easily misdiagnosed as transitional cell carcinoma. ⁴ Pathology analysis of the resected specimen combined with immunohistochemical staining for PSA are the gold standard procedures to confirm a final diagnosis. ²⁸ Importantly, prostatic-type polyps in the urethra have to be carefully differentiated from prostatic ductal carcinoma which usually presents with nuclear atypia microscopically and often has a high proliferative index; Ki-67 protein is a useful diagnostic tool for this differential analysis. ⁴

Table 1.

Overview of case reports of prostatic-type polyps located in the bladder.

Author/Year	No.	Age (years)	Site	Presentation	Procedure	Recurrence
Chan et al, 1987 6	10	39-71	Trigone*3 Neck*4 Body*3	Haematuria *8 Dysuria*2	na	na
Rubin et al. 1981 7	1	26	Trigone	Haematuria	na	na
Klein & Rosenberg, 1984 8	1	20	Trigone	Haematuria	na	na
Lubin et al, 1984 9	1	46	Trigone	Asymptomatic	na	na
Remick & Kumar,1984 10	4	43-67	Trigone*3 Left ureteral orifice*1	Dysuria*1 Haematuria *1 Asymptomatic*2	Biopsy	na
Sánchez et al, 1989 11	1	59	Neck	N/A	na	Yes
Hansen et al,1989 12	1	73	Left lateral wall	Haematuria	Transurethral resection	No
Morey et al, 1989 13	1	71	Bladder dome	Haematuria	na	na
Ishikawa e t al, 1990 14	1	58	Trigone	Haematuria	Transurethral resection	na
Richter et al, 1991 15	1	76	Trigone	Dysuria and frequency	na
Yajima et al, 1993 16	1	55	Inter-ureteric ridge	Haematuria	na	na
Anjum et al, 1997 17	2	21 & 40	Trigone	Dysuria*1Haematuria *1	Resection/fulguration	na
Yamamoto et al, 2001 18	1	35	Trigone	Asymptomatic	Transurethral resection	na
Sánchez Merino et al, 2002 19	1	58	Trigone	Asymptomatic	na	No
Dogra et al, 2002 20	1	25	Left posterolateral wall	Haematuria	Transurethral resection	No
Kumamoto & Ota, 2004 21	1	73	Bladder	Asymptomatic	Transurethral resection	na
Bellezza et al, 2005 22	3	45-79	Left urethral orifice*1Right lateral wall*1Trigone*1	Haematuria*2Asymptomatic*1	Transurethral resection	No
Oki et al, 20073 23	1	50	Verumontanum and trigone	Dysuria	Biopsy and transurethral coagulation	na
Eren et al, 2008 24	1	24	Trigone	Dysuria and voiding frequency	Transurethral resection	No
Kim et al, 2013 25	1	72	Bladder dome	Haematuria and dysuria	Transurethral resection	No
Ko et al, 20136 26	1	58	Trigone	Urinary frequency	Transurethral resection	No
Haroon &Uddin, 2014 27	2	47 & 52	Trigone	Haematuria and Urgency	Transurethral resection	No

na: data not available

From our overview of the literature, it appears that endoscopic transurethral resection is the most commonly used treatment option for prostatic-type polyps. Fulguration was used in only one of the 22 studies¹⁷ but it is an alternative treatment approach, as is partial cystectomy in certain situations.³ Since most of the prostatic-type epithelial polyps of the urinary tract are benign, the condition shows good prognosis. ²⁵ Although, investigations into the progression of prostate-type polyps into adenocarcinoma are limited, ²⁹ it appears that recurrence and progression of the disease are unlikely.^1,22 A limitation of this case report is that because the condition is rare, we were only able to study one patient. More data collection is needed for further studies.

In conclusion, among adolescent patients with suspected bladder cancer, prostatic-type polyposis should be included within the differential diagnosis. Endoscopic transurethral resection is effective in establishing the diagnosis and treatment of the condition and there appears to be good prognosis.

Declaration of conflicting interest

The authors declare that there are no conflicts of interest.