What is embryonal testicular cancer?
Embryonal testicular cancer is a type of nonseminoma (germ cell cancer), also called "mixed germ cell tumor" because it can have more than one cell type. Embryonic carcinoma is one of the four primary cell types found in nonseminoma testicular cancer.
From what I've been reading about embryonal testicular cancer, about 40 percent of testicular cancers have some cells that are embryonal, but only about 3 to 4% of nonseminomas are made up of just embryonic carcinoma cells. These tumors look like tissues of very early embryos when viewed under a microscope. This kind of tumor grows quickly and spreads outside the testicle.

