Egilmez et al. ethanol for the treatment of symptomatic renal cysts. They treated 14 patients who had renal cysts with a mean diameter of 10 cm (range: 5 15 cm). They used the following technique: US-guided percutaneous puncture with an 18-gauge needle, positioning of a 5-Fr catheter, complete cyst fluid aspiration, injection of a volume of pure alcohol equal to 15% of the initial cyst volume and alcohol aspiration after 90 min. They repeated the procedure eight times within five days. Their patients were followed up by US and/or CT scan for one year. After the study, all of their patients had become symptom free. Follow-up showed a progressive reduction of the cyst diameter in all cases. Only three cysts (in 2 patients and the cystic diameters were < 2 cm) persisted after 12 months. No significant complications were observed. They concluded that injections of pure ethanol into renal cysts and repeated for five days were effective for eliminating recurrences and the related symptoms. They did not record any significant complications. They suggested that pure ethanol sclerotherapy could be the first-choice procedure for the treatment of renal cysts instead of surgical manage- ments, and this was because of the good results and the low cost of ethanol. Percutaneous sclerotherapy is rarely associated with significant complications. We had no major complications after sclerotherapy, which is similar to the reports of other authors who found no major complications or alcohol intoxication (10, 13, 15, 16, 34). However, intense pain during filling of cysts with alcohol was reported by De Dominicis et al. (35) in a few patients who were unable to tolerate the procedure. Okeke et al. (6) found instant severe pain with a radicular distribution after ethanol injection for a painless cyst that presented as a renal mass. In our study, ten patients had transient mild flank pain that required medical management with an oral nonsteroidal anti-inflammatory drug during filling the cyst with 95% ethanol. The patients experienced n no pain during filling with 20% hypertonic saline. The optimum agent for renal cyst sclerotherapy remains to be determined. Alcohol at a 95% concentration is the most commonly used sclerosing material for cyst ablation (15, 34), and 99.8% alchohol is commonly used too (16). Several factors for achieving sucessful renal cyst sclerother- apy with alcohol require optimization, such as the concen- tration of alcohol (95% or 99%), its volume in relation to the cystic volume, the duration of sclerotherapy per session, the number of injections required in relation to the cystic volume and whether continuous drainage is needed before and after sclerotherapy. In our study, the alcohol was retained in the cyst for 20 minutes to expedite the destroying action on the cyst epithelium without the 518 alcohol penetrating the renal parenchyma or entering the circulation. A small-caliber pigtail catheter was used in our patients, with no tract dilatation, and there was no damage to the collecting system or adjacent organs. Single-session percutaneous 95% ethanol or 20% hypertonic saline sclerotherapy with CT guidance can be used for the management of simple renal cysts, and the technical success rate is close to 100%. There were no major compli- cations in our study population and no signs of intoxication with the use of sclerosant agents. In the same clinical settings, 20% hypertonic saline sclerotherapy was not as successful as 95% ethanol sclerotherapy, but it may be an alternative option for patients who prefer a less painful procedure. Our results suggest that CT-guided sclerotherapy with 95% ethanol in a single-session, and according to the protocol described in this study, is preferable as a first therapeutic option. Although the efficacy of 20% hypertonic saline sclerotherapy in our study was lower than that of the 95% ethanol sclerotherapy, 20% hypertonic saline may have a place in the armory of interventional radiologists for the managing symptomatic simple renal cysts. Further study and follow-up is needed to assess the long-term effects of 20% hypertonic saline sclerotherapy on the outcome of symptomatic simple renal cyst to determine the duration of pain for these procedures and the rates of cyst recurrence. References 1. Clayman RV, Surya V, Miller RP, Reinke DB, Fraley EE. Pursuit of the renal mass. Is ultrasound enough? Am J Med 1984;77:218-223 2. Caglioti A, Esposito C, Fuiano G, Buzio C, Postorino M, Rampino T, et al. Prevalence of symptoms in patients with simple renal cysts. BMJ 1993;306:430-431 3. Ravine D, Gibson RN, Donlan J, Sheffield LJ. An ultrasound renal cyst prevalence survey: specificity data for inherited renal cystic diseases. Am J Kidney Dis 1993;22:803-807 4. Marumo K, Horiguchi Y, Nakagawa K, Oya M, Ohigashi T, Asakura H, et al. Incidence and growth pattern of simple cysts of the kidney in patients with asymptomatic microscopic hematuria. Int J Urol 2003;10:63-67 5. Rockson SG, Stone RA, Gunnells JC Jr. Solitary renal cyst with segmental ischemia and hypertension. J Urol 1974;112:550-552 6. Okeke AA, Mitchelmore AE, Keeley FX, Timoney AG. A comparison of aspiration and sclerotherapy with laparoscopic de-roofing in the management of symptomatic simple renal cysts. BJU Int 2003;92:610-613 7. el-Diasty TA, Shokeir AA, Tawfeek HA, Mahmoud NA, Nabeeh A, Ghoneim MA. Ethanol sclerotherapy for sympto- matic simple renal cysts. J Endourol 1995;9:273-276 8. Chung BH, Kim JH, Hong CH, Yang SC, Lee MS. Comparison of single and multiple sessions of percutaneous sclerotherapy for simple renal cyst. BJU Int 2000;85:626-627 9. Fontana D, Porpiglia F, Morra I, Destefanis P. Treatment of Korean J Radiol 8(6), December 2007