Computed tomography in the diagnosis of renal parapelvic cysts

The appearances of 34 parapelvic cysts diagnosed by computed tomography (CT) in 29 patients are described. The majority were found as an incidental finding but some caused hydrocalycosis and, in one instance, hypertension. Their etiology, CT features, and differential diagnosis are discussed. The specificity of CT in these cases eliminates the need for invasive diagnostic procedures.