Ectopic pregnancy accounts for approximately 2% of all pregnancies and is the most common cause of pregnancy-related mortality in the first trimester. Initial evaluation consists of β-hCG and pelvic ultrasonography. The fallopian tube is the most common location for an ectopic pregnancy. Other types of ectopic pregnancy include cornual, ovarian, cervical, scar, and abdominal pregnancy. In very rare cases, the abdominal pregnancy may be retroperitoneal. The diagnosis is seldom established before surgery and therapy is surgical resection of the ectopic mass. A 26-year-old woman visited our emergency department with sudden massive vaginal bleeding. She had undergone curettage 3 weeks before. But the transvaginal sonogram of the cul-de-sac revealed no fl uid collection. She failed variable-dose methotrexate therapy. On laparoscopic operation, we found a cystic, conception-like structure in the retroperitoneum. Histology of resected structure showed chorionic villi. We describe this case with a brief review of the literature.

Collision tumor means the coexistence of two adjacent, but histologically distinct tumors without histologic admixture in the same tissue and is rare incidence involving ovary. Because of their incidence of occurrence, benign cystic teratomas often occur coincidentally with other abnormalities of the ovary. Most common histologic combination of collision tumor in the ovary is coexistence of teratoma with mucinous tumors. But its association with serous tumor has been noted rare and incidence is unknown. We have experienced a case laparoscopic treatment of a huge serous cystadenoma combined with ovarian benign cystic teratoma in right ovary, and report it with a brief review of literature.