[Endodermal sinus tumor (yolk sac tumor)--report of 52 cases and review of the literature of 1224 cases].

52 cases of endodermal sinus tumors (EST) are reported and 1224 cases from the Chinese and foreign literature are reviewed. This tumor, occurring usually in the gonads and rarely at extragonadal sites, comprised 10-17.1% of the former. It is located on or along the mid-line of the body including the orbit and other organs. In this paper, there are two cases with the tumor located at the orifice of urethra and one case between the pubic bone and the urinary bladder which has never been reported. EST often occurs in people under the age of 35. EST in the gonadal sites is divided into infant-childhood and adult groups. In the former group the prognosis is better than that of the adult group when the tumor is located in the testis as well as those in the vagina. There is sex and age difference for some EST in extragonadal sites. Those in the mediastinum almost always occur in young males. Diagnosis is easily made by pathology and by serum alpha-fetal protein (SAFP). Pathologically it is divided into two types: simple EST and EST element mixed with other germ cell tumors which give the same prognosis. The authors suggest that SAFP be done for any patients with teratomata in order to avoid misdiagnosis. SAFP is not only diagnostic but also prognostic by monitering postoperative course. EST is a highly malignant tumor, rapidly growing and poor in prognosis. Recent reports show that operated patients supplemented by chemotherapy give much better results than by radiotherapy.