Urolithiasis in Malignant Hematologic Diseases et al.11 asserted that when patients with acute leukemia were diagnosed as staghorn calculi, it was important to distinguish urolithiasis from hemorrhagic cystitis due to the side effects of chemotherapy, and attention should be paid to the similarity of the symptoms. In our study, we have some limitations for diagnosis because we surveyed patients who consulted our clinic for symptoms that were suspicious of urolithiasis. Therefore, it is possible that symptoms of urolithiasis were in fact neglected or mistaken for those seeming side effects of chemotherapy given in other departments. We did not per- form an analysis of urolithiasis in our study, therefore we cannot confirm the accurate composition of the stones. However, the most basic test to diagnose urinary stones is a simple X-ray of the KUB, and the level of radiopacity on KUB enables us to infer the composition of urinary stones indirectly.12 The total ratio of radiolucent stones in patients with hematologic diseases was much higher than that for general patients. Yet the control group was limited to patients with confirmed urolithiasis and who visited the emergency room. So this cannot completely represent the general population. ESWL is inadequate to completely remove stones in the group of patients with malignant hematologic diseases because of the existence of radiolucent stones or hema- tologic abnormalities, and many cases were unsuitable for invasive ureteroscopic lithotripsy due to the chemotherapy patients were receiving or their generally poor condition. Further studies on the risk factors associated with the incidence of urolithiasis, the electrolyte levels of serum or urine, and an analysis of the composition of urinary stones need to be done in the near future. In conclusion, the incidence rate of urolithiasis and radio- lucent stone in the group of patients with malignant hematol- ogic diseases was higher than that in the group of general patients. We cannot definitely find out the pathophysi- ology of the stone in this study. However, close attention should be paid to the possibility of misdiagnosing urolithi- asis because of the treatment side effects for malignant hematologic diseases. ACKNOWLEDGEMENTS Presented in Joint Annual Meeting of American Urological Association, Anaheim, California (19-24 May 2007) REFERENCES 1. Leusmann DB, Blaschke R, Schmandt W. Results of 5,035 stone analyses: a contribution to epidemiology of urinary stone disease. Scand J Urol Nephrol 1990;24:205-10. 2. Howard SC, Kaplan SD, Razzouk BI, Rivera GK, Sandlund JT, Ribeiro RC, et al. Urolithiasis in pediatric patients with acute lymphoblastic leukemia. Leukemia 2003;17:541-6. 3. Curhan GC, Willett WC, Rimm EB, Stampfer MJ. A prospective study of dietary calcium and other nutrients and the risk of sym- ptomatic kidney stones. N Engl J Med 1993;328:833-8. 4. Hesse A, Siener R. Current aspects of epidemiology and nutrition in urinary stone disease. World J Urol 1997;15:165-71. 5. Kim SC, Moon YT, Hong YP, Hwang TG, Choi SH, Kim KJ, et al. Prevalence and risk factors of urinary stones in Koreans. J Korean Med Sci 1998;13:138-46. 6. Jabbour E, Ribrag V. [Acute tumor lysis syndrome: update on therapy.] Rev Med Interne 2005;26:27-32. 7. Hiçsönmez G. The effect of steroid on myeloid leukemic cells: the potential of short-course high-dose methylprednisolone treat- ment in inducing differentiation, apoptosis and in stimulating myelopoiesis. Leuk Res 2006;30:60-8. 8. Rubin MR, Bilezikian JP. Clinical review 151: The role of para- thyroid hormone in the pathogenesis of glucocorticoid-induced osteoporosis: a re-examination of the evidence. J Clin Endocrinol Metab 2002;87:4033-41. 9. Bolan CD, Greer SE, Cecco SA, Oblitas JM, Rehak NN, Leitman SF. Comprehensive analysis of citrate effects during platelet- pheresis in normal donors. Transfusion 2001;41:1165-71. 10. Pui CH, Roy S 3rd, Noe HN. Urolithiasis in childhood acute leu- kemia and nonHodgkin’s lymphoma. J Urol 1986;136:1052-4. 11. Jaing TH, Hung IJ, Lin CJ, Chiu CH, Luo CC, Wang CJ. Acute myeloid leukemia complicated with staghorn calculus. Jpn J Clin Oncol 2002;32:365-7. 12. Pietrow PK, Preminger GM. Evaluation and medical manage- ment of urinary lithiasis. In: Wein AJ, Kavoussi LR, Novick AC, Partin AW, Peters CA, editors. Campbell-Walsh Urology. Phila- delphia: Saunders; 2007. p.1393-430. Yonsei Med J http://www.eymj.org Volume 51 Number 2 March 2010 247