Seyed Mohammad Kazem Aghamir - Urology research Center, Tehran University of Medical Sciences, Tehran, Iran
Fatemeh Khatami - Urology research Center, Tehran University of Medical Sciences, Tehran, Iran
Hamidreza Zia - Urology research Center, Tehran University of Medical Sciences, Tehran, Iran

Introduction   Renal cysts are sacs of fluid with a thin wall usually with no symptoms and have no connection to the renal calyx. Another renal lesion that can be misdiagnosed with cysts is the calyceal diverticulum with a connection to the renal calyx. The new approach of laparoscopic injection of methylene blue can help the surgeon to distinguish renal cysts from calyceal diverticulum in a patient with no double J (Dj/JJ). Case presentation A 52-years patient with a 15 cm lesion underwent laparoscopic surgery of a renal cyst. Surgery was done in the flank position and the peritoneoscopy was performed after cyst reveal. At the bottoms of the cyst, several small cysts were observed so we inject methylene blue to make it clear this lesion was exactly cysts, not calyceal diverticulum. When it was proven that there is no leaking of blue color to the renal calyx through the catheter. The cyst was revealed and was removed and sent for pathology. Conclusions In our study, the laparoscopic injection of methylene blue indicated no connection with renal calyx so the lesion is renal cysts.  So it can be a new approach for distinguishing cyst from calyceal diverticulum.

renal cyst, calyceal diverticulum, Laparoscopy