The bladder is a hollow organ located in the pelvis which stores urine that it gradually receives from the kidneys after filtration. Once full, it takes a spherical shape. The bladder stores urine until a sufficient quantity, usually 250-300 ml, and then sends signals to the brain to trigger the urge to urinate. As the kidneys produce urine continuously, absence or bladder diseases cause the patient to urinate constantly.
The bladder is like a balloon that constantly adapts to the volume it contains while maintaining a constant pressure during filling. It receives urine through the ureters from the kidneys and empties through the urethra which traverses the prostate located just below the bladder. Emptying of the bladder requires both the release of the occlusion system (sphincter) located at the outlet of the bladder, and active contraction of the muscle fibers in the wall of the bladder.
This is an important organ but it can be pathologically affected. The main medical conditions of the bladder are infections, cystitis; tumors, polyp, bladder cancer. The term “polyp” is generally used to describe benign or “superficial” tumors. Regardless of the condition or bladder cancer staging, these diseases can lead to serious complications without proper treatment. Please see bladder cancer treatment section.
Cancer of bladder is, in term of frequency, after prostate cancer, the second most common cancer of the urinary tract. It is much more common in men than in women. In the USA, it is the fourth most common cancer in men and the ninth most common cancer in women, according to the American Cancer Society (ACS).
Superficial Bladder Tumors – Most bladder tumors are superficial, the cancer cells do not deeplyinfiltrate the wall of the bladder. Depending on the case, they are called polyps, papilloma, superficial tumors, or others. The polyps usually look like a raspberry or an anemone whose fringes (the base of the polyps) are implanted in the bladder wall and float in the urine like seaweed on the ocean’s surface. The tumor may be single or multiple, papillary (fringed) or relatively nonpapillary (sessile). In some cases, the polyps occupy the greater part of the bladder lining, leaving little healthy bladder mucosa; this is called bladder papillomatosis.
Carcinoma In Situ – Besides superficial tumors, the bladder can also have a form of non-invasive cancer called carcinoma in situ. In this case, the condition is characterized by a flat papillary tumor, not located within the thickness of the mucosa. It can be unique, about 10% of cases; or associated with one or more polyps, which is often the case.
Invasive Bladder Cancer – These forms of tumors are usually more serious and the cancer cells deeply invade the bladder wall. Invasive bladder cancers spread to the muscle wall of the bladder, and sometimes in other part of the body. An Invasive bladder cancer treatment is more systematic, and removal of the gland (cystectomy) is generally recommended for the survival of the patient. Although considered as the standard treatment for this cancer, radical cystectomy is a major procedure that radically changes the lives of patients underwent the surgery. Please see bladder cancer surgery for information.
About 90% of bladder tumors are urothelial carcinoma of the bladder because they develop from the urothelium, group of cells that lines much of the urinary tract including the bladder wall.
Rarely, some bladder tumors can be non-urothelial; this occurs especially when the tumor is related to chronic irritation to the bladder wall by stones, schistosomiasis(also known as bilharzia of the bladder), and others. Some forms of exceptional rare bladder tumor include: melanoma (cancerous), pheochromocytoma (usually noncancerous), lymphoma (cancerous), and choriocarcinoma (cancerous and aggressive).