Germ cell tumors are growths that form from reproductive cells. Tumors may be cancerous or noncancerous. Most germ cell tumors that are cancerous occur as cancer of the testicles (testicular cancer) or cancer of the ovaries (ovarian cancer).
Some germ cell tumors occur in other areas of the body, such as the abdomen, brain and chest, though it's not clear why. Germ cell tumors that occur in places other than the testicles and ovaries (extragonadal germ cell tumors) are very rare.
Germ cell tumors tend to respond to treatment and many can be cured, even when diagnosed at a late stage.