Renal cystic disease refers to a heterogeneous entity of various causes, including simple or complicated cysts, hereditary polycystic disease, and developmental cystic diseases such as multicystic dysplastic kidney, acquired cystic disease, and cystic lesions associated with von Hippel-Lindau disease or tuberous sclerosis. The diagnosis is often made on the basis of the clinical history and imaging findings, and it is sometimes difficult to differentiate benign from malignant cystic lesions.