stage 0 bladder carcinoma in situ

Abnormal cells are found in tissue lining the inside of the bladder. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is divided into stages 0a and 0is, depending on the type of tumor. Stage 0a is also called noninvasive papillary carcinoma, which may look like long, thin growths growing from the lining of the bladder. Stage 0is is also called carcinoma in situ, which is a flat tumor on the tissue lining the inside of the bladder.