A urothelial cell is a special cell type that lines the inner surface of the bladder, ureters, and urethra. The bladder is an organ which collects, and stores urine produced by the kidneys. Urine travels from the kidneys to the bladder by two tubes called ureters and is leaves the bladder by the urethra.
Urothelial cells connect to form a barrier on the inside of the bladder called an epithelium. In the bladder, the epithelium is given the special name urothelium. The urothelium is designed to stretch as the bladder fills with urine.
There are several types of cancer that can start from urothelial cells but the most common two types are urothelial carcinoma and papillary carcinoma. If the cancer cells are only seen in the epithelium, the disease is called urothelial carcinoma in situ.