A small cyst is a fluid-filled sac and located in the kidneys. Also known as renal cysts, many renal cysts are benign, and people can live their entire lives without any knowledge of a cyst. In other cases, are a source of concern, and the doctor may recommend a follow-up treatment may include surgery to remove a kidney cyst when a cyst is identified through a medical examination and testing. Classically, renal cysts were identified on ultrasound, MRI or other medical imaging studies. In the case of a simple cyst, the cyst appears as a fluid-filled sac, and if the cyst is aspirated, may contain a clear yellowish fluid, sometimes mixed with blood. Complex renal cysts, however, irregularities, such as calcification, which means it is a solid material inside the cyst, or develop the interior walls. Complex renal cyst is a cause of concern as it may be associated with the development of kidney cancer.
