[A very unusual tumor: inverted papilloma of the bladder]

Based on a personal series of 10 cases seen over a 10 year period, the characteristics of the inversed bladder papilloma are reviewed. Affecting men mainly, and presenting nonspecific signs (hematuria, disorders of micturition or secondary infections), these lesions can be detected by urography and particularly cystoscopy, enabling their extraction by endoscopic resection and histological examination. Histology findings serve to exclude some other tumors or pseudotumors (papillary tumors, urothelial carcinoma, proliferative cystitis). Various histogenic theories are discussed, preference being given to suppression of the term inversed papilloma in favor of adeno-urothelioma. Recurrence after treatment occurred in one case only. One patient had an inversed papilloma associated with a papillary tumor. Typical histology findings and usual benign course enable a good prognosis to be given for these curious tumors.