Bladder, ureter & renal pelvis

Other nonneoplastic

Prostatic type polyp


Editorial Board Member: Debra L. Zynger, M.D.
Deputy Editor-in-Chief: Maria Tretiakova, M.D., Ph.D.
Bonnie Choy, M.D.

Topic Completed: 14 September 2021

Minor changes: 14 September 2021

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PubMed Search: Prostatic type polyp

Bonnie Choy, M.D.
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Cite this page: Choy B. Prostatic type polyp. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/bladderprostatepolyp.html. Accessed December 3rd, 2021.
Definition / general
  • Uncommon, nonneoplastic urothelial tract polyp comprised of prostatic glands and stroma
Essential features
  • Polypoid or papillary lesion consists of nonneoplastic prostatic glandular epithelium with 2 distinct cell layers (luminal / secretory layer and basal layer) and corpora amylacea
  • Immunoreactive for prostate specific antigen (PSA) and prostatic acid phosphatase (PAP)
  • Most important differential to consider and exclude is prostatic ductal adenocarcinoma
Terminology
  • Ectopic prostate
  • Benign prostatic epithelial polyp
  • Adenomatous polyp with prostatic type epithelium (historically used)
  • Papillary adenoma with prostatic type epithelium (historically used)
ICD coding
  • ICD-10: N32.9 - bladder disorder, unspecified
Epidemiology
Sites
Etiology
Clinical features
Diagnosis
  • Cystoscopy with biopsy or transurethral resection
  • Histologic examination of tissue
Radiology description
  • Transrectal ultrasonography (Clin Imaging 2013;37:778)
    • Homogeneous isoechogenicity, similar to the bladder wall
    • No significant high blood flow on color Doppler ultrasound
Prognostic factors
Case reports
Treatment
Clinical images

Images hosted on other servers:
Smooth sessile mass on cystoscopy

Smooth sessile mass on cystoscopy

Spherical mass on cystoscopy

Spherical mass on cystoscopy

Gross description
Microscopic (histologic) description
  • Polypoid or papillary
  • Nonneoplastic prostatic type glandular epithelium within stroma (Histopathology 1987;11:789, Am J Surg Pathol 1984;8:833, Int Urol Nephrol 1997;29:313, Histopathology 2011;58:750)
    • Prostatic acini vary in number and may contain corpora amylacea
    • 2 distinct cell layers: luminal epithelial cell layer and basal cell layer
      • Luminal layer: cuboidal to columnar cells with round nuclei and frothy, faintly eosinophilic cytoplasm, some containing eosinophilic granules
      • Basal cell layer: between luminal layer and basement membrane, typically elongated and flattened cells with slender nuclei and minimal cytoplasm
  • Interspersed urothelium may be associated with cystitis cystica and cystitis glandularis
Microscopic (histologic) images

Contributed by Bonnie Choy, M.D.
Polypoid

Polypoid

Admixture of urothelium and prostatic acini

Admixture of urothelium and prostatic acini

Corpora amylacea

Corpora amylacea

PSA positive

PSA positive

Cytology description
Sample pathology report
  • Urinary bladder, biopsy:
    • Prostatic type polyp (see comment)
    • Comment: Immunohistochemistry for PSA and PSAP highlight the glandular epithelium within the polypoid lesion, confirming prostatic origin.
Differential diagnosis
  • Prostatic ductal adenocarcinoma:
    • More complex architecture, including cribriform and anastomosing cords
    • Pseudostratified columnar epithelium
    • Low grade nuclear features but with prominent nucleoli
    • IHC: PSA and PAP also positive
  • Urothelial carcinoma with glandular differentiation:
    • More complex architecture
    • Cytologic atypia seen in both urothelial and glandular components
    • Pseudostratified columnar epithelium lining glands
    • IHC: CK7 and GATA3 positive in urothelial component but negative in glandular component
  • Papillary urothelial neoplasm:
    • Papillary architecture with more complexity - secondary or tertiary branching
    • Stratified epithelium
    • No glandular component
    • IHC: CK7 and GATA3 positive
  • Benign prostatic hyperplasia:
    • Variable amounts of benign prostatic glands and spindle cells
    • May form polypoid mass protruding into the bladder near the bladder neck
  • Nephrogenic metaplasia (adenoma):
    • Variable patterns, including mixed papillary and polypoid with tubules in the underlying stroma
    • Single cuboidal layer of epithelial cells
    • IHC: PAX8, CK7 and AMACR positive, may occasionally show weak positivity for PSA or PAP
  • Polypoid / papillary cystitis:
    • Architecture may mimic prostatic type polyp
    • No prostatic glandular epithelium, no corpora amylacea
    • IHC: PSA and PAP negative
  • Cystitis cystica / glandularis:
    • Cystic and gland-like structures of varying size and shape lined by urothelium
    • May have polypoid appearance
    • No prostatic glandular epithelium, no corpora amylacea
    • IHC: PSA and PAP negative
Board review style question #1
Polypoid PSA positive


A 40 year old man with gross hematuria is found to have a polypoid mass in the bladder trigone on cystoscopy. A transurethral resection of the bladder mass shows the above histologic features. Immunohistochemistry for PSA was performed. What is the likely diagnosis?

  1. Nephrogenic adenoma
  2. Polypoid cystitis
  3. Prostatic ductal adenocarcinoma
  4. Prostatic type polyp
Board review style answer #1
D. Prostatic type polyp. Prostatic type polyp consists of benign prostatic acini admixed with urothelium. PSA positivity confirms prostatic origin. Nephrogenic adenoma can demonstrate mixed papillary, polypoid, tubular and tubulocystic patterns lined by a single cuboidal layer of epithelial cells, unlike the 2 cell layers present in prostatic glands. Polypoid cystitis may have similar architecture as prostatic type polyp. However, polypoid cystitis does not contain prostatic glands and is negative for PSA. While PSA is immunoreactive in both prostatic type polyp and prostatic ductal adenocarcinoma, morphologic features, such as complex architecture, pseudostratified columnar epithelium and prominent nucleoli (not seen in the above image), support the latter.

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Reference: Prostatic type polyp
Board review style question #2
Which of the following is true regarding prostatic type polyp?

  1. Behaves in benign fashion, with low recurrence rate
  2. Marked cytologic atypia present
  3. Most commonly seen at anterior wall of the bladder
  4. Patients often present with elevated PSA
Board review style answer #2
A. Behaves in benign fashion, with low recurrence rate. Prostatic type polyp is a nonneoplastic process, with low potential for recurrence. Patients most frequently present with hematuria. Other presenting symptoms include hematospermia, dysuria and urinary outflow obstruction. In the urinary bladder, the most common site is the trigone. Morphologic features show benign prostatic type glandular epithelium admixed with urothelium.

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Reference: Prostatic type polyp
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