Dysgerminoma with a slightly elevated alpha-fetoprotein level diagnosed as a mixed germ cell tumor after recurrence

A pure dysgerminoma shows a normal serum alpha-fetoprotein level, and mixed germ cell tumors containing endodermal sinus tumor elements have elevated serum alpha-fetoprotein levels, ranging from >100 to far higher than 1,000 ng/ml. A 40-year-old woman was diagnosed as having a stage Ia pure dysgerminoma with a slight alpha-fetoprotein elevation (11 ng/ml), after a staging laparotomy, because we could not find any yolk sac element in the original tumor. After 44 months, she had a pelvic recurrent tumor with a significant elevation of the serum alpha-fetoprotein concentration (1,520 ng/ml); histological examination of a needle biopsy specimen revealed a typical yolk sac tumor. Eventually, her initial tumor was diagnosed as a mixed germ cell tumor. The patient was successfully treated with seven courses of chemotherapy and has been disease free for 22 months. It is necessary to be aware of the possibility of a mixed germ cell tumor containing a yolk sac element, even when the alpha-fetoprotein level is only slightly elevated.