Prostate gland & seminal vesicles

Other nonneoplastic lesions

Urethral polyp


Editorial Board Member: Bonnie Choy, M.D.
Deputy Editor-in-Chief: Maria Tretiakova, M.D., Ph.D.
Y. Albert Yeh, M.D., Ph.D.

Topic Completed: 11 August 2021

Minor changes: 11 August 2021

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PubMed search: urethral polyp prostate pathology

Y. Albert Yeh, M.D., Ph.D.
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Cite this page: Yeh YA. Urethral polyp. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/prostateurethralpolyp.html. Accessed December 3rd, 2021.
Definition / general
Essential features
  • Prostatic type urethral polyp is characterized by delicate papillae with true fibrovascular cores lined with prostatic epithelium with focal benign urothelial cells; prostatic acini are often present in the polyp (Am J Surg Pathol 1983;7:351)
  • Fibroepithelial urethral polyp is composed of cloverleaf-like and club-like dense fibrovascular cores covered by benign urothelium (Am J Surg Pathol 2005;29:460)
Terminology
  • Prostatic type urethral polyp, also known as prostatic urethral polyp and prostatic type epithelial polyp of the urethra (J Urol 2015;193:2095)
  • Fibroepithelial urethral polyp, also known as fibroepithelial congenital urethral polyp (J Pediatr Surg 2014;49:835)
ICD coding
  • ICD-10:
    • N36.9 - urethral disorder, unspecified
    • D30.4 - benign neoplasm of urethra
Epidemiology
  • Prostatic type urethral polyp:
  • Fibroepithelial urethral polyp:
    • Age range 17 - 70 years, mean of 47 years (Am J Surg Pathol 2005;29:460)
    • Commonly occurs in pediatric males, usually 3 - 9 years of age (Can J Urol 2013;20:6974)
    • Rare patients present during infancy or adulthood
    • Rarely occurs in pediatric female patients
Sites
  • Commonly occurs in posterior prostatic urethra adjacent to verumontanum or the bladder neck (J Urol 2015;193:2095)
  • Anterior urethra in rare case reports
Pathophysiology
  • Ectopic prostatic acinar epithelium presents focally in urothelial tract, commonly in posterior urethra, rarely in bladder neck and penile urethra
  • Prostatic type urethral polyp likely caused by hyperplastic proliferations of the prostatic acinar epithelium results in overgrowth of the overlying urothelium (Am J Surg Pathol 1984;8:833)
Etiology
Clinical features
  • Common symptoms and signs: hematuria, dysuria, hemospermia
  • Urethrocystoscopic examination: a polypoid mass protruding from the posterior urethral wall (most common) or from anterior urethral wall (Urology 2020;143:238)
Diagnosis
  • Ultrasonography reveals a protruding hyperechogenic polypoid mass protruding from the posterior (most common) urethral wall (Urology 2020;143:238)
  • Filling defect on voiding cystourethrogram (Clin Imaging 2018;51:164)
  • Appearance of a benign polyp on urethrocystoscopy followed by histopathological examination of the excised polyp
Radiology description
  • Abdominal sonogram of the urinary bladder shows a hyperechogenic polypoid mass protruding to the bladder neck (Urol J 2020;18:86)
  • Filling defect is present at the bladder neck of a distended bladder (Clin Imaging 2018;51:164)
Radiology images

Images hosted on other servers:

Polypoid mass

Filling defect

Prognostic factors
  • Excellent prognosis for prostatic type urethral polyp and fibroepithelial urethral polyp
  • Recurrence is unusual (J Urol 2015;193:2095)
Case reports
Treatment
Clinical images

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Urethrocystoscopic view of polyp

Gross description
  • Prostatic type urethral polyp (J Urol 2015;193:2095)
    • Pink-tan, exophytic papillary, filiform to rarely sessile structure
    • Single or multiple polyps
    • Usually < 1 cm
  • Fibroepithelial urethral polyp (Clin Imaging 2018;51:164)
    • Pink-tan, polypoid mass with narrow stalk
    • Usually < 4 cm
Gross images

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Brown-tan knob-like polyp

Microscopic (histologic) description
  • Prostatic type urethral polyp:
    • Delicate papillae with true fibrovascular cores lined by an outer layer of columnar cells and an underlying flattened to cuboidal basal cells (Am J Surg Pathol 1983;7:351)
    • Focal benign urothelium is present in the benign prostatic epithelium (J Urol 2015;193:2095)
    • Benign prostatic acini are present in the papillae and in adjacent fibromuscular stroma (J Urol 2015;193:2095)
  • Fibroepithelial urethral polyp (Am J Surg Pathol 2005;29:460):
    • Pattern 1: most common pattern includes the following features
      • Broad cloverleaf-like and club-like projections covered by normal urothelium and composed of dense fibrovascular stroma with florid cytitis cystica et glandularis (most common morphologic variant)
      • Back to back glands present in the stalk
      • Anastomosing nests of benign urothelial cells resembling inverted papilloma
      • Dilated cysts with intracystic papillary contents
      • Degenerative reactive atypia of stromal cells
    • Pattern 2: numerous small papillae with dense fibrous cores and areas of glandular differentiation
    • Pattern 3: urothelial lined broad edematous papillae mimicking polypoid urethritis; urothelial lined broad fibrous papillae with subepithelial edema
Microscopic (histologic) images

Contributed by Y. Albert Yeh, M.D., Ph.D.

Fibroepithelial polyp
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Polypoid mass

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Cloverleaf-like and club-like projections

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Broad based papillae

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Cloverleaf-like projections

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Club-like projections


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Broad based finger-like papillae

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Urethritis cystica and glandularis

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Polypoid and club-like projections

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Focal calcifications

Cytology description
Cytology images

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Benign papillary cluster

Positive stains
Negative stains
Sample pathology report
  • Urethral lesion, prostatic, excision:
    • Urethral polyp with prostatic type epithelium and changes, consistent with prostatic type urethral polyp (see comment)
    • Comment: The urethral lesion shows a polypoid and papillary growth lined by prostatic type epithelium and composed of benign prostatic acini. PSA and PSAP immunohistochemical stains reveal positive cytoplasmic staining in the prostatic glandular cells. These features are consistent with prostatic urethral polyp.
  • Urethral lesion, prostatic, excision:
    • Cloverleaf-like and club-like projections lined by normal urothelium, consistent with fibroepithelial urethral polyp (see comment)
    • Comment: The urethral lesion shows papillary projections arranged in cloverleaf-like and club-like pattern. The papillary structures are composed of broad fibrovascular cores covered by unremarkable urothelial cells. Neither urothelial proliferation nor epithelial atypia is noted. These features are consistent with fibroepithelial urethral polyp.
Differential diagnosis
Board review style question #1

A 50 year old man presented with dysuria and hematuria for 3 months. Cystoscopic examination showed a polypoid mass protruded from the posterior wall of the prostatic urethra. Cystoscopic excision of the polyp and histopathological examination were performed. The microphotograph of the urethral polyp is shown above. What is the diagnosis?

  1. Fibroepthelial urethral polyp
  2. Polypoid urethritis
  3. Prostatic type urethral polyp
  4. Urethral caruncle
Board review style answer #1
A. Fibroepithelial urethral polyp

Comment here

Reference: Urethral polyp
Board review style question #2
A 40 year old man presented with dysuria for 2 months. During cystoscopy, a polypoid mass protruding from the posterior urethra was detected. Surgical excision of the polyp was performed and microscopic examination showed a papillary growth lined by tall benign columnar cells with pale eosinophilic cytoplasm. In the stroma are some glands lined by benign columnar cells with underlying flattened epithelial cells. What is the diagnosis?

  1. Fibroepithelial polyp
  2. Polypoid urethritis
  3. Prostatic type urethral polyp
  4. Urethral caruncle
Board review style answer #2
C. Prostatic type urethral polyp

Comment here

Reference: Urethral polyp
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