Testicular Cancer
Testicular cancer is cancer that develops in one or both testicles in men or young boys. Testicle cancer 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.
Over 90 percent of cancers of the testicle develop in certain cells known as germ cells. ("Germ" means seed; the term refers to the role of male germ cells in producing sperm cells.) There are two main types of germ cell tumors (GCTs) in men: seminomas and nonseminomas. Many testicle tumors contain features of both types. Because of the way these "mixed" tumors grow, spread and respond to treatment, they are classified as being nonseminomas.
About half of all testicle germ cell cancers are seminomas. They develop from the sperm-producing germ cells of the testicle. There are two main subtypes of these tumors distinguished by their appearance under the microscope — typical (or classic) seminomas (found usually in men in their 30s through 50s) and spermatocytic seminomas (usually found in men in their 50s). Over 90 percent of seminomas are typical. Most spermatocytic tumors grow very slowly and usually do not metastasize (spread to other parts of the body). The average age of men who are diagnosed with spermatocytic seminoma is 65, about 15 years older than the average age of men with typical seminomas.
Nonseminoma germ cell cancers tend to develop earlier in life than seminomas, usually occurring in men in their 20s. There are three main types of nonseminoma germ cell cancers. Embryonal carcinomas, which account for about 20 percent of testicle tumors, tend be aggressive, which means they are likely to metastasize and grow rapidly. Yolk sac carcinomas are the most common form of testicular cancer in infants and young boys. When they occur in young children, these tumors usually are successfully treated. When yolk sac tumors develop in adults, however, they are more dangerous, especially if they do not contain other types of nonseminoma cells. Choriocarcinomas are a very rare and aggressive type of testicle cancer of adults.