If you have BHD, you may get kidney cysts. Kidney cysts are rounded sacs usually filled with fluid. There are two types of cysts – simple and complex.
Simple kidney cysts do not affect kidney function and are common in older people. Around one in every five people over the age of 50 have kidney cysts. Usually, it is difficult to know if you have cysts, as they rarely cause symptoms. They are often discovered by accident, during a test or scan for something else. Occasionally, a simple cyst can cause pain if it is pressing on another organ, or if it becomes infected. Treatment for a simple kidney cyst is only required if it becomes infected or if it affects the function of the kidney or another organ.
A complex cyst has a more irregular shape or thicker walls than a simple cyst. In general, the larger the cysts and the more complex their shape, the more likely it is to turn into a cancer. While most kidney cysts will not become cancerous, everyone with BHD should have regular scans of their kidney. Therefore, if a complex cyst does become cancerous it can be monitored and treated early.