A cyst is a closed pocket or pouch of tissue that can form anywhere in the body. Cysts can be filled with air or fluid. Cysts that form on the kidneys usually contain fluid. One or more cysts may develop on small tubes in the kidneys. The simple kidney cyst is different from the cysts that develop when a person has polycystic kidney disease, which is a genetic disease. Although its cause is not fully understood, the simple cyst is not an inherited condition. Simple kidney cysts become more common as people age. Nearly 30 percent of people over the age of 70 have at least one simple kidney cyst.
Simple kidney cysts are abnormal pouches containing fluid. The simple cyst is the most common form of kidney cyst. Although its cause is not fully understood, we do know that the simple cyst is not an inherited condition. Cysts may be single or multiple and develop on small tubes in the kidneys.
