What is childhood extracranial germ cell tumor?

Germ cells are reproductive cells that develop into testicles in males and ovaries in females. Sometimes these cells travel to other areas of the body, such as the chest, abdomen, or brain, and may turn into a rare type of cancer called germ cell tumor. This summary covers germ cell tumors that occur extracranially (everywhere but in the brain).

Extracranial germ cell tumors can be benign (not cancerous) or malignant (cancerous). Most germ cell tumors are benign and are very rare in children younger than age 15. Germ cell tumors of early childhood have biological characteristics which are different than those that occur in adolescents and young adults. The location of the tumor and the age of the child make a difference in the prognosis (chance of recovery) and in how the tumor is treated. The major types of germ cell tumors by location and age are:

Testicular germ cell tumors of early childhood

This type of germ cell tumor forms within the testis of young boys. The treatment for this type of germ cell tumor is covered later in this summary.

Testicular germ cell tumors of adolescence and young adulthood

This type of germ cell tumor forms within the testes of older boys. Testicular germ cell tumors are classified as either seminoma or nonseminoma. This classification is important for planning treatment because seminomas are more sensitive to radiation therapy. (Refer to the PDQ summary on Testicular Cancer for more information.)

Extragonadal, extracranial germ cell tumors of early childhood

This includes any type of germ cell tumor that is not located in the reproductive organs (testicles or ovaries) or in the brain. These germ cell tumors are usually located in the sacrum (a triangular-shaped section of fused bone located between the hip bones at the base of the spine ) and the coccyx (the fused bones located on the end of the sacrum; also called the tailbone). The treatment for this type of germ cell tumor is covered later in this summary.

Extragonadal, extracranial germ cell tumors of adolescence and young adulthood

This type of germ cell tumor is usually located within the chest. The treatment for this type of germ cell tumor is covered later in this summary.

Ovarian germ cell tumors

Ovarian germ cell tumor, a rare type of cancer that affects teenage girls and young women, is a disease in which cancer (malignant) cells are found in egg-making cells in an ovary. An ovary is a small organ that holds the eggs that can develop into a baby. There are 2 ovaries: one located on the left side of the uterus (the hollow, pear-shaped organ where a baby grows) and one located on the right. The treatment for this type of germ cell tumor is covered later in this summary (refer to the PDQ summary on Ovarian Germ Cell Tumors for more information).

Germ cell tumors form in developing cells and usually contain tissues that are foreign to the location of the tumor. Germ cell tumors can further be classified as teratomas or malignant germ cell tumors. Teratomas can be either mature (well differentiated tissue that forms a tumor that is less likely to become cancer) or immature ( undifferentiated tissue that can spread and become cancer). Most teratomas are mature and develop into benign tumors.