Transitional cell bladder cancer (TCC) is the most common type of bladder cancer. Nearly all cancers of the bladder start in the layer of cells (transitional cells) which form the lining of the bladder (transitional epithelium). These cancers are called transitional cell or urothelial cell cancers.

Bladder cancer may appear as a tumour which has grown into the muscle wall of the bladder. This is known as invasive bladder cancer.

Bladder cancer may also begin as a small growth only on the inner lining of the bladder (called papillary cancers). Sometimes these early cancers can start to grow into the muscle of the bladder and become invasive bladder cancer.

Carcinoma in situ (CIS) is a type of early bladder cancer which appears as a red, ulcerated area in the bladder. In CIS the cells are very abnormal or high-grade, so it can grow quickly. If it’s not treated effectively, there’s a high risk that CIS will become an invasive cancer.

Rarer types of bladder cancer are squamous cell cancer and adenocarcinoma. Squamous cell cancers start from one of the types of cell in the bladder lining. Adenocarcinoma starts from glandular cells which produce mucus. Both of these types are usually invasive.