Polypoid cystitis

Abstract

• Polypoid cystitis is an uncommon urinary tract disorder of dogs that causes hematuria and other signs of lower urinary tract inflammation.

• It is thought that chronic inflammation in the urinary bladder may lead to epithelial and stromal proliferation, eventually leading to polyp formation.

• Typically, the polyps consist of proliferative epithelium surrounding inflamed, hemorrhagic, connective tissue stroma. Grossly, the bladder mucosa may be thrown up into folds or may have villous mucosal projections up to several cm in length. In some cases, the bladder wall simply appears abnormally thickened, but histopathologic examination reveals typical polypoid changes.

• Polypoid cystitis usually develops in the cranial ventral bladder wall, whereas transitional cell carcinomas more commonly arise from the bladder neck region. Grossly, it is impossible to distinguish polyps from carcinomas with complete confidence and histopathologic confirmation of the diagnosis is required.