Bladder tumors are lumps of malignant cells that form in the tissues of the bladder. Malignant tumors are cancerous and can start in any of the cells in the bladder. Therefore, the cancers are named depending on where they started, as stated by the National Cancer Institute.
There are three types of bladder cancer that start as tumors in the lining of the bladder. The first type of bladder cancer is the transitional cell carcinoma, which starts in the cells located in the inner layer of the bladder. It is categorized into two types: low-grade and high-grade transitional cell carcinoma. Low-grade carcinoma returns after treatment but rarely spreads to other parts, while high-grade carcinoma returns after treatment and spreads to other parts of the body.
The cancer that starts in the squamous cells of the bladder is referred to as squamous cell carcinoma. Squamous cells tend to form in the bladder after an infection. Even though it is rare, adenocarcinoma is a type of bladder cancer that starts in the grandular cells, which are located in the bladder lining.
Cancer that is only in the bladder lining is usually referred to as superficial bladder cancer. One that starts in the lining of the bladder and spreads to the other organs is called invasive bladder cancer, according to the National Cancer Institute.