Prevalence of symptoms in patients with simple renal cysts

few anecdotal reports have indicated simple renal cysts as a possible cause of hypertension, flank pain, macroscopic haematuria, and erythrocytosis.'-3 Many physicians also believe that simple renal cysts commonly cause microscopic haematuria and mild proteinuria. The frequency of association of simple renal cysts with any of these symptoms, however, has never been the object of controlled epidemiological study, and certain important questions therefore lack definite answers. For example, should further diagnostic procedures (such as renal biopsy) be performed, after simple renal cysts are found in a patient with mild proteinuria or microscopic haematuria? Is the prevalence of flank pain or macroscopic haematuria in patients with simple renal cysts so high as to justify invasive procedures (such as removal by surgery or the application of alcohol)?