Most cancers are named for the part of the body or type of cells in which they begin. About 90 percent of bladder cancers are transitional cell carcinomas, cancers that begin in the cells lining the bladder. Cancer that is confined to the lining of the bladder is called superficial bladder cancer. After treatment, superficial bladder cancer can recur; if this happens, most often it recurs as another superficial cancer.

In some cases, cancer that begins in the transitional cells spreads through the lining of the bladder and invades the muscular wall of the bladder. This is known as invasive bladder cancer. Invasive cancer may grow through the bladder wall and spread to nearby organs.

Bladder cancer cells may also be found in the lymph nodes surrounding the bladder. If the cancer has reached these nodes, it may mean that cancer cells have spread to other lymph nodes and to distant organs, such as the lungs. The cancer cells in the new tumor are still bladder cancer cells. The new tumor is called metastatic bladder cancer rather than lung cancer because it has the same kind of abnormal cells that were found in the bladder.