ObjectiveTo assess the feasiblity of using ultrasonic endoscopy in retroperitoneal laparoscopic nephron-sparing surgery for treatment of endogenous renal tumor, and to summarize our clinical experience.MethodsA female patient, aged 28 years old, was found to have a mass (diameter 1.4 cm×1.0 cm, clinical stage T1aN0M0) in the right upper part of the kidney. Retroperitoneal laparoscopic nephron-sparing surgery was performed. The tumor could not be accurately located during the operation due to the smooth renal surface; then ultrasonic endoscopy was used to locate the tumor; and color Doppler mode was used to observe the blood supply of the tumor and its relation with surrounding tissues. The nephron-sparing surgery was performed following the guidance of ultrasonic endoscopy positioning; the integrity of tumor resection and surgical margin were also observed.ResultsThe involvement of the tumor and its blood supply were clearly displayed by ultrasonic endoscopy. No noticeable signals of blood flow were seen around the tumor after blocking the renal artery, and the tumor was totally and thoughly removed with a negative margin of 0.5-1.0 cm. There was no transfer to opening surgery. The procedure of ultrasonic endoscopy lasted for 5 min. Postoperative pathological results indicated angiomyolipoma with negative margins.ConclusionOur initial clinical practice suggests that ultrasonic endoscopy is safe and benificial for retroperitoneal laparoscopic nephron-sparing surgery in treatment of endogenous renal tumors, especially for observing the tumor location, tumor blood supply, and the integrity of resection.