•The etiology of squamous metaplasia is dependent upon the underlying pathologic process, i.e, bladder calculi, extrophy of the bladder, schistosomiasis.

•Probably normal in women.

•The normal transitional epithelium will undergo squamous metaplasia as an adaptive change to chronic irritation, such as from bladder calculi.

•The epidemiology is dependent on the underlying disease process.

•Squamous metaplasia is found in a large percentage of women with no abnormalities.

•Squamous metaplasia may occur in situations of chronic irritation such as bladder calculi, extrophy of the bladder and schistosomiasis.

•There is no striking gross changes to the epithelial lining of the bladder.

•There may be a perception that the epithelial lining is paler and thicker than normal.

•The normal transitional epithelium of the bladder is replaced by stratified squamous epithelium.

• Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 48

• Current literature from PubMed at National Library of Medicine