Benign and low-grade papillary lesions of the urinary bladder: a review of the papilloma-papillary carcinoma controversy, and a report of five typical papillomas.
The controversial topic concerning the most appropriate nomenclature for low-grade papillary lesions of the urinary bladder is reviewed on the basis of the literature and the authors' experiences. This undertaking was prompted by a recent report in which use of the designation "papilloma" was advocated for lesions that generally had been diagnosed as grade 1 papillary urothelial carcinoma. The literature indicates that 10% to 20% of patients with a noninvasive low-grade papillary tumor of the bladder will later have invasive bladder cancer. This significant outcome in a minority of such patients warrants very careful follow-up for the group as a whole, irrespective of the terminology used. The authors contrast the features of papillary urothelial carcinoma with a series of five cases, which they interpret as true papillomas. They believe that these low-grade papillary lesions can be distinguished from true papillomas and do not favor a change in terminology. Some of the problems in the evaluation of inverted papilloma and inverting urothelial carcinoma are briefly reviewed as are other selected papillary lesions of the urinary bladder.