What are kidney cysts?

Renal cysts are fluid-filled cystic structures formed within the kidneys, typically presenting as round or oval-shaped formations filled with liquid. Their causes are varied and mainly include the following: 1. **Simple renal cysts**: Generally develop from renal tubular diverticula. With aging, the number of diverticula increases, which may eventually develop into renal cysts. These cysts are usually acquired later in life and are mostly benign. 2. **Complex renal cysts**: These cysts may contain septa, blood, infections, or calculi. Their formation may be related to further evolution of simple renal cysts or may be associated with genetic factors or other disease conditions. 3. **Polycystic kidney disease**: This is a hereditary disorder caused by congenital genetic factors. Numerous small cysts develop on the kidneys and gradually enlarge with age, potentially leading to impaired kidney function over time.