Laparoscopically Resected Venous Adventitial Cystic Disease that was Difficult to Distinguish from an Ovarian Tumor.

Adventitial cystic disease (ACD) is a rare condition in which a mucinous cyst forms within the adventitia, usually in arteries but rarely in veins. A 79-year-old patient presented with stomachache and nausea. Computerized tomography showed pelvic cysts on either side of the pelvis. The right tumor was 120×100 mm, and the left tumor was 45×35 mm. Our diagnosis was bilateral ovarian tumors and we performed laparoscopic tumor resection. In the abdominal cavity, we saw that the left ovary was swollen by about 3-4 cm and the right ovary was normal size. There was a mucous cyst located in the right retroperitoneal cavity that adhered around and bordered the right external iliac vein and the right obturator nerve. We peeled the adhesion away carefully and resected the tumor but the operation caused temporary obturator nerve paralysis. From pathological examination, we diagnosed the right retroperitoneal cyst to be venous ACD originating from the right external iliac vein. We found that venous ACD can grow as large as a pelvic tumor and is difficult to distinguish from an ovarian tumor, which is why we chose laparoscopic surgery. In this case, we performed the operation laparoscopically and no sequelae or recurrent tumor appeared during a 1-year follow-up. However, graft replacement is sometimes necessary for ACD, thus venous ACD should be considered a differential diagnosis and a surgical strategy should be developed when pelvic tumors are observed.