General Information About Childhood Extracranial Germ Cell Tumors
Key Points for This Section
- Childhood extracranial germ cell tumors form from germ cells in parts of the body other than the brain.
- Childhood extracranial germ cell tumors may be benign or malignant.
- There are three types of extracranial germ cell tumors.
- Childhood extracranial germ cell tumors are grouped as gonadal or extragonadal.
- The cause of most childhood extracranial germ cell tumors is unknown.
- Having certain inherited disorders can increase the risk of an extracranial germ cell tumor.
- Signs of childhood extracranial germ cell tumors depend on the type of tumor and where it is in the body.
- Imaging studies and blood tests are used to detect (find) and diagnose childhood extracranial germ cell tumors.
- Certain factors affect prognosis (chance of recovery) and treatment options.
A germ cell is a type of cell that forms as a fetus (unborn baby) develops. These cells later become sperm in the testicles or eggs in the ovaries. Sometimes while the fetus is forming, germ cells travel to parts of the body where they should not be and grow into a germ cell tumor. The tumor may form before or after birth.
See the PDQ summary on Childhood Central Nervous System Germ Cell Tumors Treatment for information on intracranial (inside the brain) germ cell tumors.
Mature teratomas are the most common type of extracranial germ cell tumor. Mature teratomas are benign tumors and not likely to become cancer. They usually occur in the sacrum or coccyx (bottom part of the spine) in newborns or in the ovaries of girls at the start of puberty. The cells of mature teratomas look almost like normal cells under a microscope. Some mature teratomas release enzymes or hormones that cause signs and symptoms of disease.
Immature teratomas also usually occur in the sacrum or coccyx (bottom part of the spine) in newborns or the ovaries of girls at the start of puberty. Immature teratomas have cells that look very different from normal cells under a microscope. Immature teratomas may be cancer. They often have several different types of tissue in them, such as hair, muscle, and bone. Some immature teratomas release enzymes or hormones that cause signs and symptoms of disease.
Malignant germ cell tumors are cancer. There are two main types of malignant germ cell tumors:
- Germinomas: Tumors that make a hormone called beta-human chorionic gonadotropin (β-hCG). There are three types of germinomas.
- Dysgerminomas form in the ovary in girls.
- Seminomas form in the testicle in boys.
- Germinomas form in areas of the body that are not the ovary or testicle.
- Nongerminomas: There are four types of nongerminomas.
- Yolk sac tumors make a hormone called alpha-fetoprotein (AFP). They can form in the ovary, testicle, or other areas of the body.
- Choriocarcinomas make a hormone called beta-human chorionic gonadotropin (β-hCG). They can form in the ovary, testicle, or other areas of the body.
- Embryonal carcinomas may make a hormone called β-hCG and/or a hormone called AFP. They can form in the testicle or other parts of the body, but not in the ovary.
- Mixed germ cell tumors are made up of both malignant germ cell tumor and teratoma. They can form in the ovary, testicle, or other areas of the body.
Gonadal germ cell tumors form in the testicles in boys or ovaries in girls.
Testicular Germ Cell Tumors
- Seminomas make a hormone called beta-human chorionic gonadotropin (β-hCG).
- Nonseminomas are usually large and cause signs or symptoms. They tend to grow and spread more quickly than seminomas.
Testicular germ cell tumors usually occur before the age of 4 years or in teenagers and young adults. Testicular germ cell tumors in teenagers and young adults are different from those that form in early childhood.
Boys older than 14 years with testicular germ cell tumors are treated in pediatric cancer centers, but the treatment is much like the treatment used in adults. (See the PDQ summary on Testicular Cancer Treatment for more information.)
Ovarian Germ Cell Tumors
Ovarian germ cell tumors are more common in teenage girls and young women. Most ovarian germ cell tumors are benign teratomas. Sometimes immature teratomas, dysgerminomas, yolk sac tumors, and mixed germ cell tumors (cancer) occur. (See the PDQ summary on Ovarian Germ Cell Tumors Treatment for more information.)
Extragonadal extracranial germ cell tumors form in areas other than the brain, testicles, or ovaries.
Most extragonadal extracranial germ cell tumors form along the midline of the body. This includes the following:
- Sacrum (the large, triangle-shaped bone in the lower spine that forms part of the pelvis).
- Coccyx (the small bone at the bottom of the spine, also called the tailbone).
- Mediastinum (the area between the lungs).
- Back of the abdomen.
In younger children, extragonadal extracranial germ cell tumors usually occur at birth or in early childhood. Most of these tumors are teratomas in the sacrum or coccyx.
In older children, teenagers, and young adults, extragonadal extracranial germ cell tumors are often in the mediastinum.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your child’s doctor if you think your child may be at risk.
Possible risk factors for extracranial germ cell tumors include the following:
- Having certain genetic syndromes:
- Klinefelter syndrome may increase the risk of germ cell tumors in the mediastinum.
- Swyer syndrome may increase the risk of germ cell tumors in the testicles or ovaries.
- Turner syndrome may increase the risk of germ cell tumors in the ovaries.
- Having an undescended testicle may increase the risk of developing a testicular germ cell tumors.
Different tumors may cause the following signs and symptoms. Other conditions may cause these same signs and symptoms. Check with a doctor if your child has any of the following:
- A lump in the abdomen or lower back.
- A painless lump in the testicle.
- Pain in the abdomen.
- In females, no menstrual periods.
- In females, unusual vaginal bleeding.
The following tests and procedures may be used:
- Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. The testicles may be checked for lumps, swelling, or pain. A history of the patient's health habits and past illnesses and treatments will also be taken.
- Serum tumor marker test : A procedure in which a sample of blood is checked to measure the amounts of certain substances released into the blood by organs, tissues, or tumor cells in the body. Certain substances are linked to specific types of cancer when found in increased levels in the blood. These are called tumor markers.
Most malignant germ cell tumors release tumor markers. The following tumor markers are used to detect extracranial germ cell tumors:
- Alpha-fetoprotein (AFP).
- Beta-human chorionic gonadotropin (β-hCG).
- Blood chemistry studies : A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.
- Chest x-ray : An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The picture can be printed to be looked at later.
- Biopsy : The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. In some cases, the tumor is removed during surgery and then a biopsy is done.
The following tests may be done on the sample of tissue that is removed:
- Cytogenetic analysis : A laboratory test in which cells in a sample of tissue are viewed under a microscope to look for certain changes in the chromosomes.
- Immunohistochemistry : A test that uses antibodies to check for certain antigens in a sample of tissue. The antibody is usually linked to a radioactive substance or a dye that causes the tissue to light up under a microscope. This type of test may be used to tell the difference between different types of cancer.
- The type of germ cell tumor.
- Where the tumor first began to grow.
- The stage of the cancer (whether it has spread to nearby areas or to other places in the body).
- Whether the tumor can be completely removed by surgery.
- The patient's age and general health.
- Whether the cancer has just been diagnosed or has recurred (come back).
The prognosis for childhood extracranial germ cell tumors, especially ovarian germ cell tumors, is good.