Abstract

The germ cells first appear from the primitive streak, the splanchnopleure and the allantoic membrane of the embry and they migrate toward the gonadal ridge. It can happen, however, that some of these germ cells may not migrate to the gonadal ridge and may remain at ectopic sites such as the mediastium, the central nervous system, the sacrococcygeal region and the retroperitoneum. Therefore, germ cell tumors can arise from these ectopic sites and according to their totipotentiality of differentiating into embryonic and extraembryonic tissues, such as chorionic tissues and yolk sac, they can develop into various tumors. Generally, the sites in which these tumors are frequently found are the gonads, the sacrococcygeal region, the mediastinum, the retroperitoneum and the intracranial region. The aim of this study was to organize and report the data found on these tumors in the records of 412 patients whose tumor specimens were examined in the Department of Pathology of the Yonsei University, college of Medicine within the 10 year period, 1976~1985. The findings are as follows: 1) In total 412 cases, the ratio of benign to malignant tumors was 5.8:1. 2) Germ cell tumors occur commonly in the ovary (326 cases: 78.6%). It's incidence was followed by the descending order, in the mediastinum (26 cases: 6.3%), testis (23 cases: 5.6%), central nervous system (15 cases: 3.6%), sacrococcygeal region (11 cases: 2.7%) and retroperitoneal space (7 cases: 1.7%). Also, 2 were found in the intraorbital region and 1 each in the pericardium and the kidney. 3) In extragonadal sites, female were much more common and the sex ratio (M:F) showed 1:10 in sacrococcygeal region. 1:2.5 in retroperitoneum and 1:2.3 in mediastinum. 4) Mature teratoma was found most commonly (85.4%). It's incidence was followed by in descending order, seminoma (including dysgerminoma and germinoma) (6.8%), embryonal carcinoma (2.9%), endodermal sinus tumor (2.0%), immature teratoma (1.7%) and mixed forms (1.2%). 5) Benign teratoma takes up mostly at ovary, retroperitoneal space, sacrococcygeal region and mediastinum by 93.3%, 100.0%, 81.8%, 80.9%, respectively. But in testis and intracranial region, malignancy were more common. 6) Embryonal carcinoma and endodermal sinus tumor occured at similar aged group and each was distributed 41.7% and 62.5% respectively at first decade. 87.5% of dysgerminoma occured at 11~30 aged group, 91.7% of germinoma at 11~20 aged group, 67% mature teratoma at 20~40 aged group, 75% of seminoma at 31~50 aged group, so age distribution showed embryonal carcinoma, endodermal sinus tumor, dysgerminoma/germinoma, mature teratoma and seminoma, in increasing order. 7) In 352 cases of mature teratoma, 347 cases (98.6%) were cystic type and 5 cases (1.4%) were solid type. In 7 cases of immature teratoma, 5 cases (71.4%) were solid and 2 cases (28.6%) were cystic. 8) The incidence of bilaterality were 10.2% in mature teratoma, 12.5% in dysgerminoma and 16.7% in seminoma. 9) When the corredation of the tumor markers, alphafetoprotein and human chorionic gonadotropin, with malignancy was checked in 12 out of 28 cases of tumor of the testis. Either alpha fetoprotein of human chorionic gonadotropin was found to be elevated in 3 cases (75%) in which metastasis was already present at the time of diagnosis, where in 8 cases in which neither marker was elevated, metastasis was found to be present in only 1 (12.8%).