Teratomas often occur in the gonads, while Extragonadal mature cystic teratomas are reported occasionally, with the most common site being the omentum. Teratoma in the Douglas sac is extremely rare. we report a rare case of mature cystic Teratoma in the Douglas sac in a 71-year-old woman who underwent laparoscopic surgery. A cyst with a diameter of approximately 6 cm from Douglas was found during surgery, and the mass was separated from both ovaries. Microscopically, the cyst was a mature cystic teratoma that did not originate from the ovary.

Compared with traditional laparotomy, laparoscopic surgery has obvious advantages (smaller incisions, shorter hospital stays, and reduced blood loss). At present, more and more gynecological surgeries can be completed under laparoscopy. With the increasement of clinical treatment of gynecological laparoscopic surgery, the complications related to gynecological laparoscopic surgery and their prevention measures have become a continuous concern in the field of gynecology. The risk of injury to the lower urinary tract, consisting of the bladder and ureters, is inherent to gynecologic surgery regardless of operative technique, because the bladder and ureters lie adjacent to other critical structures. Ureteral injury caused by gynecological laparoscopic surgery is a relatively rare complication. Clinicians do not pay enough attention to it because of its low incidence. However, once it happens, the consequences are often serious. The clinical manifestations of ureteral injury caused by gynecological laparoscopic surgery vary greatly according to the location and severity of the injury. Patients with mild injury can heal themselves after conservative treatment, and patients with severe injury can have serious consequences such as peritonitis and acute renal insufficiency, and even lead to death. This paper will focus on ureteral anatomy, common causes, clinical manifestations, key points of diagnosis, treatment measures and prevention strategies of ureteral injury caused by laparoscopic surgery.