There are 3 main types of bladder cancer. These are named after the cell type in which the cancer first develops. 

• Urothelial carcinoma (or transitional cell carcinoma) is the most common type of bladder cancer, making up more than 80–90% of bladder cancers ^[1]. It starts in the cells in the inside layer of the bladder wall (urothelial cells). This type of cancer sometimes occurs in the ureters and kidneys ^[2], and can move into the muscle wall of the bladder or to other parts of the body ^[3].  
• Squamous cell carcinoma is the next most common type of bladder cancer, making up about 1–2% of bladder cancers. It starts in the thin, flat cells that line the bladder (squamous cells) and is more likely to be invasive ^[4]. This type of cancer may develop after a long-term infection or irritation ^[5].  
• Adenocarcinoma is a rare type of bladder cancer, making up 1% of bladder cancers. It starts in glandular cells that line the bladder and is likely to be invasive ^[6].  

Other rare types of bladder cancer include sarcoma, small cell carcinoma, plasmacytoid carcinoma and micropapillary carcinoma ^[7]. These occur rarely in less than 1% of bladder cancer cases.