Renal cyst versus tumor: a continuing dilemma.

We report on 13 patients with renal cystic lesions who underwent full radiological investigation and remained undiagnosed preoperatively. Of 13 cysts 3 ultimately proved to be malignant at surgical exploration. A retrospective review of these cases failed to reveal any additional features that would have aided in preoperative diagnosis. Despite the high accuracyobtainable by radiological investigation, diagnostic surgical exploration is warranted in a small proportion of patients with renal cystic lesions.