Clinical Evaluation of Parapelvic Renal Cysts: Do These Represent Latent Urological Malignant Disease?

Purpose: The parapelvic renal cyst is a relatively common finding on routine urological examination, butonly rarely needs treatment. We here examined all parapelvic renal cyst patients who consulted our Departmentbetween April 1998 and December 2004 with the focus on potential for malignant development. Materials and
Methods: A total of 73 patients were diagnosed as having parapelvic renal cysts by ultrasonography, incombination with computed tomography, and/or drip infusion urography in our Department. The backgroundto diagnosis was suspicion of hydronephrosis in 15, flank and/or back pain in 15, and macroscopic hematuriaand/or occult blood urine in 12.
Results: There were 3 patients with renal pelvic cancer, and one patient withureteral cancer. Nephro-ureterectomy was performed for all of these 4 cases. There were 10 patients with renalstones, three of which were given extracorporeal shock wave lithotripsy and one pyelonephrolithotomy. A furtherthree underwent parapelvic renal cyst puncture, performed to preserve renal function or obtain release fromsymptoms. The remaining 3 cases were symptomless, diagnosed after routine examinations, and were simplyfollowed up, as with the other 59 cases with no stones or cancer.
Conclusions: Unless a parapelvic renal cystcauses pyelonephritis, symptomatic renal stones, or back discomfort, treatment is not indicated. However, thepossibility that urological malignant disease may be encountered should be borne in mind and appropriatediagnostic measures should be performed. Furthermore, careful follow up of parapelvic renal cyst patients maybe required.