Germ cell tumors are malignant (cancerous) or non-malignant
(benign, non-cancerous) tumors that are comprised mostly of germ
cells. Germ cells are the cells that develop in the embryo (fetus,
or unborn baby) and become the cells that make up the reproductive
system in males and females. These germ cells follow a midline path
through the body after development and descend into the pelvis as
ovarian cells or into the scrotal sac as testicular cells. Most
ovarian tumors and testicular tumors are of germ cell origin. The
ovaries and testes are called gonads.
They are rare, as only about 2.4 children in one million will
develop one of these tumors in a given year. Germ cell tumors
account for 4 percent of all cancers in children and adolescents
under the age of 20 years.
Germ cell tumors can spread (metastasize) to other parts of the
body. The most common sites for metastasis are the lungs, liver,
lymph nodes, and central nervous system. Rarely, germ cell tumors
can spread to the bone, bone marrow, and other organs.
Embryonal carcinoma cells are malignant cells that are usually
mixed with other types of germ cell tumors. They occur most often
in the testes. These types of cells have the ability to spread to
other parts of the body. When these cells are mixed with an
otherwise benign type of tumor (mature teratoma), the presence of
embryonal carcinoma cells will cause it to become malignant
(cancerous).
