Renal cell carcinoma developed in a patient treated with huge simple renal cyst sclerotherapy

Simple renal cysts are a common cystic disease of the kidneys, which is not symptomatic in most cases and is diagnosed by radio -logical examination. However, if the cyst is huge or symptomatic, it must be treated. Renal cyst aspiration and alcohol sclerot herapy is a safe and effective treatment for symptomatic simple renal cysts. Simple renal cysts have benign clinical features in the m ain and transformation of a simple renal cyst into renal cell carcinoma has rarely been reported. However, one case of renal cell carci noma during renal cyst follow‐up has been reported. We report a case of renal cell carcinoma that developed in a patient who was being treated with huge simple renal cyst sclerotherapy. (Korean J Med 79:201-205, 2010)