teratocarcinoma
Chapter: 17
A malignant germ cell tumor composed of embryonal carcinoma cells, which act as stem cells of the tumor, and their differentiated derivatives. The descendants of malignant stem cells may remain malignant or differentiate into mature nonproliferating tissues. Malignant components of teratocarcinomas belong usually to the extra-embryonic lineages: trophoblastic, placenta-like cells, forming choriocarcinoma elements, and cells corresponding to the extraembryonic yolk sac, known as yolk sac carcinoma. Choriocarcinoma cells secrete human chorionic gonadotropin (hCG), whereas yolk sac carcinoma cells secrete alpha fetoprotein (AFP). AFP and hCG are elevated in the blood of teratocarcinoma bearing patients and serve as serologic markers of this testicular malignancy.
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