The Urology Center Glossary terms

Kidney Cysts:

Cysts of the kidney are fluid filled structures that usually lie within the parenchyma (meaty portion) of the kidney. Kidney cysts are extremely common and perhaps half of all middle-aged or older adults have cysts of the kidney! Obviously, most cysts represent incidental findings on x-ray studies which are generally performed for unrelated reasons. Likewise, most kidney cysts are benign but some cysts represent cancer or a potential cancer of the kidney.

Cysts are classified primarily according to their appearance on CT scans and ultrasound scans. The Bosniak kidney cyst classification system was originally proposed in 1986 and is the most widely used classification method. So-called "simple" kidney cysts are round structures with thin tissue walls and no solid material nor debris within the fluid filled center of the cyst. If a cysts meets the qualifications to be called a simple cyst, there is little possibility for complications such as pain or development of kidney cancer. More complicated kidney cysts are inconsistent in appearance and irregular. A complicated cyst may have a cyst wall which is thickened, calcified or misshapen and the normally fluid filled center may contain solid portions (or at least radiographic suspicion of solid center portions). The more complicated appearing the cyst, the greater the chance of cancer within or near the cyst.

Some kidney cysts cause pain but most cysts cause no symptoms at all. Obviously, when cysts cause significant pain or if a cyst is suspicious for associated kidney cancer, surgical intervention is required. Intervention for pain caused by benign simple kidney cysts may entail x-ray guided needle drainage of the cyst with injection of a sclerosing agent into the cyst. The sclerosing agent injection treatment is sometimes successful in causing scarring within the cyst, causing it to shrivel-up or shrink. Alternatively, all or part of a cyst may be removed by laparoscopic or open surgical procedures.

"When malignancy is in question, the part of the kidney containing the cyst may be treated with laparoscopic or percutaneous cryosurgical freezing, allowing the remaining kidney to be preserved."

When malignancy is in question, the part of the kidney containing the cyst may be treated with laparoscopic or percutaneous cryosurgical freezing, allowing the remaining kidney to be preserved. Urologists at the Urology Center are now performing this new procedure. Alternatively, when cancer is a possibility, the part of the kidney containing the cystis removed or the entire kidney is removed.

A number of medical conditions are commonly associated with kidney cysts. In such cases multiple kidney cysts are usually present in both kidneys and cysts may also be present in other organs such as the liver. Diseases, such as polycystic kidney disease commonly run families, often causing kidney failure. Von Hippel Lindau disease is another kidney disease associated with multiple bilateral kidney cysts. However, generally unlike polycystic kidney disease, von Hippel Lindau diseases is commonly associated with the development of kidney cancer!

Urologists and nephrologists are the most qualified the medical professionals to distinguish between the potentially serious kidney cysts which may be associated with kidney cancer or kidney failure, verses benign simple kidney cysts which generally require no treatment at all.

(See related glossary terms: "kidney cancer", "nephrology")