Testicular cancer is cancer that typically develops in one or both testicles in young men. It is a highly treatable and usually curable form of cancer.
The testicles contain several types of cells, each of which may develop into one or more types of cancer. It is important to distinguish these types of cancers from one another because they differ in their prognosis (the outlook for chances of survival) and in the ways they are treated.
Germ Cell Tumors
Over 90% of cancers of the testicle develop in certain cells known as germ cells. (Germ means seed; these are the cells that produce sperm.) The 2 main types of germ cell tumors (GCTs) that occur in men are seminomas (60%) and nonseminomas (40%). (The suffix -oma means tumor.) Although some cancers contain both nonseminoma and seminoma cells, they are classified as nonseminomas because they grow and spread like nonseminomas. These tumors can be separated into 2 major categories, according to their differences in appearance under the microscope, different patterns of spread, and somewhat different responses to treatment.
Seminomas develop from the sperm-producing germ cells of the testicle. The 2 main subtypes of these tumors are classical (or typical) seminomas and spermatocytic seminomas. Doctors can tell them apart by how they look under the microscope. Over 95% of seminomas are classical. These usually occur in men when they are between their late 30s and early 50s. This is an older population than those with nonseminomas.
The average age of men diagnosed with spermatocytic seminoma is about 55, which is 10 to 15 years older than the average age of men with typical seminomas. Spermatocytic tumors are different from classical seminomas. They grow very slowly and usually do not spread to other parts of the body.
These germ cell cancers tend to develop earlier in life than seminomas, usually occurring in men between their late teens and early 40s. The main types of nonseminomas are embryonal carcinoma, yolk sac carcinoma, choriocarcinoma, and teratoma. Most tumors are mixed with at least 2 different types, but this does not change treatment. All nonseminoma germ cell cancers are treated the same way, so the exact type of nonseminoma is not that important.
Drew Voight - Men's Health