[An early combined endodermal sinus tumor of the ovary that was diagnosed due to torsion of serous cystadenoma--a case report].

Reported is a rare case of a 2.5cm endodermal sinus tumor (EST) that was included within a 11 x 10.5 cm serous cystadenoma. A 24-year-old female suddenly complained of abdominal pain caused by having undergone an intestinal torsion of a left ovarian tumor. After a unilateral salpingo-oophorectomy the serum AFP was 219.8 ng/ml. The patient then received two cycles of cis-platinum, vinblastine and bleomycin combination chemotherapy. After one cycle, the serum AFP decreased to a normal level and the woman has remained free of disease 6 months after the discovery of her tumor. In this case, fortunately, this torsion of a serous cystadenoma enabled us to find the EST at a very early stage.