Background and Aim: Mullerian duct remnant (MDR) is a rare condition and is sometimes accidentally diagnosed during surgery for an inguinal hernia and undescended testes. MDR is always found near the seminal duct and conservatively preserved, preventing injury of the seminal duct. However, recent reports have revealed that MDR has the potential to become malignant.1,2 Cases of deaths among male adolescents have also been reported. As such, surgical extirpation of MDR is recommended. Laparoscopic and robotic approaches have been applied as surgical intervention.3,4 In this video, the combination of laparoscopy and cystoscopy to safely extirpate an MDR is shown. Materials and Methods: Case: A four-month-old boy was initially found to have coronal hypospadias and undescended testes. Laparoscopy was performed at 11 months of age because of nonpalpable testes. A left streak gonad and MDR were found to be presenting as a complete uterus and vagina. Chromosomal examination revealed mixed gonadal dysplasia (46XY (23)/45X (7)). A cystoscope showed that the MDR was connected to the prostatic urethra. At 18 months of age, this patient underwent extirpation of the left streak gonad and urethroplasty for hypospadias. Subsequently, resection of the MDR was planned because of repeated urinary tract infections. Operative Findings and Procedure: The patient was placed in a lithotomy position and a cystoscope was used to confirm the fistula orifice at the urethra. A 5 mm, 30° laparoscope was inserted through the umbilical longitudinal incision. Pneumoperitoneum was established at 8 mmHg CO2 inflation. Two 5 mm ports (left upper abdomen and left lower abdomen) and one 3 mm port (right lower abdomen) were inserted. MDR presenting as a complete uterus and vagina was recognized. The bladder was suspended using extracorporeal 3-0 proline insertion. The bilateral uterus ligaments were coagulated and divided using a vessel sealing system (LigaSure Maryland; Medtronic, Inc., Dublin, Ireland). After opening the peritoneal reflection, the distal side of the MDR was carefully dissected using a 3 mm bipolar (RoBi, KarlStorz, Tuttling, Deutschland) to prevent thermal injury of the pelvic nerve. The distal mullerian duct had a vaginal appearance and was connected to the urethra as a fistula. Before ligation of the fistula, the depth of dissection was confirmed using a cystoscope. Under inspection with the cystoscope, the dissected fistula was retracted, and the level of dissection was confirmed. A transfixing 4-0 PDS (Ethicon, Cincinnati, OH) suture was used to ligate the fistula, which was then resected using a vessel sealing system and ligated using an Endoloop (Ethicon). No injury to the bilateral ureter or urethra was recognized. Results and Conclusion: The postoperative course was uneventful. A pathological diagnosis revealed that the resected MDR showed age-appropriate development. The patient has had a good clinical course since the operation. A laparoscopic approach is feasible and low invasive for the extirpation of an MDR, even in infants. The fistula was safely ligated using a combination of laparoscopy and a cystoscope. This combination approach is useful for preventing injury to the urethra. Acknowledgments: We thank Brian Quinn for his comments and help with the article. This study was supported by grants-in-aid for scientific research from the Japan Society for the Promotion of Science (JSPS, No. 25293360 and No. 26670765), JFE (The Japanese Foundation for Research and Promotion of Endoscopy), J-CASE (Japanese Consortium of Advanced Surgical Endoscopy), Foundation for Promotion of Cancer Research, Foundation for Shinnihon Zaidan, a research grant from the President's Discretionary Expenses of Kagoshima University, a research grant from The UBE Foundation, and a research grant from Japan Medical Education Foundation. No competing financial interests exist. Runtime of video: 6 mins 49 secs