Squamous Proliferations Other than Carcinoma



Squamous Proliferations Other than Carcinoma


Jesse K. McKenney, MD





Key Facts


Etiology/Pathogenesis



  • Keratinizing squamous metaplasia



    • May be associated with chronic irritation


    • Catheters, stones, or parasitic infection


    • Neurogenic bladder


  • Condyloma of bladder



    • Contains HPV DNA


Clinical Issues



  • Squamous papilloma



    • Elderly women


  • Condyloma



    • Young sexually active population


Microscopic Pathology



  • Nonkeratinizing glycogenated squamous mucosa



    • Very common in trigone of women


    • Normal variation in histology


  • Keratinizing squamous metaplasia



    • Hyperkeratotic squamous epithelium lining bladder lumen


  • Condyloma



    • Resembles condyloma at other sites


    • Koilocytotic cytologic features


  • Squamous papilloma



    • Papillary cores lined by cytologically benign squamous epithelium


    • No viral cytopathic effect is seen


Top Differential Diagnoses



  • Squamous dysplasia


  • Urothelial carcinoma in situ


  • Noninvasive papillary urothelial carcinoma


  • Verrucous carcinoma







Glycogenated nonkeratinizing squamous mucosa commonly occurs in the trigone and bladder neck of women. This is a normal finding and does not have any pathologic risk for progression to neoplasia.






Keratinizing squamous metaplasia may be seen in longstanding inflammatory conditions. This finding should be reported, as it may be associated with risk of obstruction or progression to neoplasia.


TERMINOLOGY


Definitions



  • Squamous metaplasia



    • Replacement of urothelium by stratified squamous epithelium



      • Nonkeratinized (except trigone) and keratinized subtypes


  • Squamous papilloma



    • Rare benign exophytic papillary squamous neoplasm



      • Unrelated to human papilloma virus (HPV) infection


  • Condyloma



    • Exophytic squamous proliferation with HPV viral cytopathic effect


  • Squamous hyperplasia, papillary and flat



    • Multiple layers of cytologically bland metaplastic squamous epithelium with flat or papillary architecture


ETIOLOGY/PATHOGENESIS


Environmental Exposure



  • Keratinizing squamous metaplasia



    • May be associated with chronic irritation



      • Catheters, stones, parasitic infection


Infectious Agents



  • Condyloma of bladder



    • Contains HPV DNA


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Isolated urinary tract involvement by condyloma is rare



      • Associated urethral, vulvar, vaginal, anal, or perineal condyloma is common


  • Age



    • Squamous papilloma



      • Elderly women


    • Condyloma



      • Young sexually active population


Endoscopic Findings



  • Squamous metaplasia



    • Pale gray-white with irregular borders, often with surrounding zone of erythema


  • Condyloma and squamous papilloma



    • Appear as exophytic polypoid lesions


Prognosis

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Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Squamous Proliferations Other than Carcinoma

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