Polypoid/Papillary Cystitis

Definition

• Polypoid reactive urothelial lesion

Diagnostic Criteria

• Predominantly composed of frond-like papillae
  • Stromal edema
  • Stromal acute and/or chronic inflammation
  • Predominantly broad based fronds
    • Thin or branching stalks unusual
  • Lined by normal to thickened transitional epithelium
  • Reactive atypia may be present
    • Uniform increase in nuclear size
    • Single uniform nucleoli
    • Mitotic figures may be present
    • No nuclear hyperchromatism or pleomorphism
      • (Umbrella cells, as always, are exceptions to this rule)
  • Arises in a setting of chronic irritation
• Older lesions may have more fibrotic, thinner stalks
  • May not always be separable from fibroepithelial polyp
  • Areas of edematous, inflammed, broad fronds generally present

Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting/updates: 10/20/12

Supplemental studies

Immunohistology

• Not applicable

Differential Diagnosis

• Papillary Urothelial Neoplasms
• Fibroepithelial polyp
• Nephrogenic adenoma
  

Papillary Urothelial Neoplasms	Papillary / Polypoid Cystitis
Delicate papillary stalks	Broad, edematous base and stalks
Lining may be atypical	Lined by normal urothelium
Frequent branching papillae	Broad fronds, little branching

Papillary / Polypoid Cystitis	Fibroepithelial Polyp
Papillae and polyps arise diffusely directly from the bladder wall	Polypoid mass from which papillae and projections arise
Generalized/diffuse process	Solitary lesion in most cases
Generalized inflammation even in late stages	Inflammation not prominent

These two may not always be separable; both are benign

Nephrogenic Adenoma	Papillary / Polypoid Cystitis
Papillae lined by single layer of cells, frequently hobnailed	Papillae lined by normal multilayered transitional epithelium
No umbrella cells	Normal umbrella cells present
Usually associated with tubular submucosal component	No associated tubular component

Grading / Staging

Grading

• Not applicable

Staging

• Not applicable

Clinical

• Not considered to be a preneoplastic lesion

Classification / Lists

Flat Lesions of the Urinary Bladder

• Flat urothelial hyperplasia
• Reactive urothelial atypia
• Atypa of unknown significance
• Dysplasia
• Urothelial carcinoma in situ

Papillary Lesions of the Urinary Bladder

• Nephrogenic adenoma
• Fibroepithelial polyp
• Polypoid/papillary cystitis
• Papillary urothelial hyperplasia
• Urothelial papilloma
• Papillary urothelial neoplasm of uncertain malignant potential (PUNLUMP)
• Low grade urothelial carcinoma
• High grade urothelial carcinoma

Subtypes of High Grade Urothelial Carcinoma

• Micropapillary urothelial carcinoma
  
• Plasmacytoid urothelial carcinoma
• Small cell carcinoma
• Urothelial carcinoma with chordoid features
• Urothelial carcinoma with sarcomatoid differentiation
• Urothelial carcinoma with squamous differentiation
  

Inverted Lesions of the Urinary Bladder

• Florid hyperplasia of von Brunn nests
• Cystitis cystica/glandularis
• Inverted urothelial papilloma
• Inverted urothelial carcinoma
• Nested variant urothelial carcinoma
• Verrucous squamous carcinoma

Glandular Lesions of the Urinary Bladder

• Nephrogenic adenoma
• Cystitis cystica/glandularis
• Intestinal Metaplasia
• Villous adenoma
• Urothelial carcinoma with glandular differentiation
• Nested urothelial carcinoma with cystic structures
• Non-urachal adenocarcinoma
• Mulllerian lesions
  • Endometriosis
  • Endocervicosis
  • Endosalpingosis
• Urachal lesions
  • Urachal remnant
  • Urachal adenocarcinoma
• Metastatic/direct spread of non-bladder adenocarcinomas

Bibliography

• Murphy WM, Grignon DJ, Perlman EJ. Tumors of the Kidney, Bladder and Related Urinary Structures, Atlas of Tumor Pathology, AFIP Fourth Series, Fascicle 1, 2004
• Eble JN, Sauter G, Epstein JI, Sesterhenn IA eds. World Health Organization Classification of Tumors. Pathology and genetics of tumors of the Urinary System and Male Genital Organs. IARC Press: Lyon 2004.
• Harik LR, O'Toole KM. Nonneoplastic lesions of the prostate and bladder. Arch Pathol Lab Med. 2012 Jul;136(7):721-34.
• Hameed O, Humphrey PA. Pseudoneoplastic mimics of prostate and bladder carcinomas. Arch Pathol Lab Med. 2010 Mar;134(3):427-43.
• Young RH. Tumor-like lesions of the urinary bladder. Mod Pathol. 2009 Jun;22 Suppl 2:S37-52.
• Lane Z, Epstein JI. Polypoid/papillary cystitis: a series of 41 cases misdiagnosed as papillary urothelial neoplasia. Am J Surg Pathol. 2008 May;32(5):758-64.