AbstractBackgroundInguinal lymphocele is a well‐known complication of inguinal lymph node dissection. Isosulfan blue has been used to identify and treat lymphoceles arising from lymphatics injured during surgery of the groin. However, the preventive use at the time of lymph node dissection has not been reported.ObjectivesWe evaluated the potential role of intraoperative injection of isosulfan blue during inguinal lymph node dissection for the prevention of postoperative lymphocele.MethodsWe performed 43 conventional inguinal lymph node dissections (group A) and 7 inguinal lymph node dissections using isosulfan blue injection around the dissected inguinal region (group B) to identify lymphatic leakage intraoperatively.ResultsLymphoceles were observed in 13 of 43 dissections (30.23%) in group A and in 0 of 7 dissections (0%) in group B. The number of detected injured lymphatics ranged from 0 to 6 (mean 3.3) in group B. The mean postoperative lymphatic drainage output was less in group B than in group A. The mean number of days of suction catheter insertion was 4.43 days in group B, and 7.98 days in group A.ConclusionsThe technique during inguinal lymph node dissection presented herein is useful for the prevention of postoperative lymphocele. J. Surg. Oncol. 2011; 104:657–660. © 2011 Wiley Periodicals, Inc.