A few cases of Fibroma and Myoma have been described, but they are rare.

Papilloma is a much commoner tumour. This is met with for the most part in the inferior parts of the bladder, and ,forms either a prominent mass with projecting papillae or else a surface covered by villi. The tendency of these villi to bleed is an important fact. Sometimes the villi break down and an ulcer forms. In any case they discharge abundant epithelium, which is to be found in the urine, and is not to be taken as evidence of the existence of cancer.

Cancer of the bladder is mostly met with in the form of villous cancer. The surface is like that of the Papilloma, but the wall of the bladder beneath the villi is infiltrated with the cancerous structures. In some cases the structure gives way and a cancerous ulcer with raised edges is the result. There are also cancers without any villous projections of the surface. These may form very insignificant tumours and yet lead to very wide-spread secondary extension. The cancer may extend to neighbouring structures, but it is much more common for a cancer originating in the uterus or rectum to extend into the bladder than for the reverse process to occur. We have already seen that fistulous communications occur in this way.

Cysts have been found, especially in the posterior wall of the bladder.