Childhood extracranial germ cell tumors start in germ cells in parts of the body other than the brain.

A germ cell is a type of cell that forms as a fetus develops. These cells later become sperm in the testicles or eggs in the ovaries.

This summary is about germ cell tumors that form in parts of the body that are extracranial (outside the brain). Extracranial germ cell tumors usually form in the following areas of the body:

• Testicles.
• Ovaries.
• Sacrum or coccyx (tailbone).
• Retroperitoneum (area in the back of the abdomen behind the tissue that lines the abdominal wall and covers most of the organs in the abdomen).
• Mediastinum (area between the lungs).
• Head and neck.

Extracranial germ cell tumors are most common in adolescents, with rates in this age group lower for females than males.

For information on intracranial (inside the brain) germ cell tumors, see Childhood Central Nervous System Germ Cell Tumors Treatment.

Childhood extracranial germ cell tumors may be benign or malignant.

Extracranial germ cell tumors may be benign (noncancer) or malignant (cancer).

Childhood extracranial germ cell tumors are grouped as gonadal or extragonadal extracranial tumors.

Malignant extracranial germ cell tumors are tumors that form outside the brain. They are gonadal or extragonadal.

Gonadal germ cell tumors

Gonadal germ cell tumors form in the gonads (testicles and ovaries).

• Testicular germ cell tumors. Testicular germ cell tumors are divided into two main types, seminoma and nonseminoma. Nonseminomas are usually large and cause signs or symptoms of disease. They tend to grow and spread more quickly than seminomas.

  Testicular germ cell tumors usually occur before the age of 5 years or in adolescents and young adults. Testicular germ cell tumors in adolescents (11 years and older) and young adults are different from those that form in early childhood.

• Ovarian germ cell tumors. Ovarian germ cell tumors are more common in adolescent girls and young women. Most ovarian germ cell tumors are benign mature teratomas (dermoid cysts). Some ovarian germ cell tumors, such as immature teratomas, dysgerminomas, yolk sac tumors, or mixed germ cell tumors, are malignant.

Extragonadal extracranial germ cell tumors

Extragonadal extracranial germ cell tumors form in areas of the body other than the brain or gonads (testicles and 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 (tailbone).
• Mediastinum (the area between the lungs).
• Back of the abdomen.
• Neck.

In children younger than 11 years, extragonadal extracranial germ cell tumors usually occur at birth or in early childhood. Most of these tumors are benign teratomas in the sacrum or coccyx.

In older children, adolescents, and young adults (11 years and older), extragonadal extracranial germ cell tumors are often in the mediastinum.

There are three types of extracranial germ cell tumors.

Extracranial germ cell tumors are also grouped into teratomas, malignant germ cell tumors, and mixed germ cell tumors:

Teratomas

There are two main types of teratomas:

• Mature teratomas. These tumors 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 in newborns or in the testicles or ovaries 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. These tumors usually occur in areas other than the gonads in young children or in the ovaries at the start of puberty. They have cells that look very different from normal cells under a microscope. Immature teratomas may be cancer and spread to other parts of the body. 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

Malignant germ cell tumors are cancer. There are two main types of malignant germ cell tumors:

• Seminomatous germ cell tumors. There are three types of seminomatous germ cell tumors:
  • Seminomas form in the testicle.
  • Dysgerminomas form in the ovary.
  • Germinomas form in areas of the body that are not the ovary or testicle, such as the mediastinum.
• Nonseminomatous germ cell tumors. There are four types of nonseminomatous germ cell tumors:
  • 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 (beta-hCG). They can form in the ovary, testicle, or other areas of the body.
  • Embryonal carcinomas may make a hormone called beta-hCG. They can form in the testicle or other areas of the body, but not in the ovary.
  • Gonadoblastomas can form in the ovary.

Mixed germ cell tumors

Mixed germ cell tumors are made up of at least two types of malignant germ cell tumor. They can form in the ovary, testicle, or other areas of the body.

The cause of most childhood extracranial germ cell tumors is unknown.

Having certain inherited disorders can increase the risk of extracranial germ cell tumors.

A risk factor is anything that increases the chance of getting a disease. Not every child with one or more of these risk factors will develop an extracranial germ cell tumor. And it will develop in some children who don't have a known risk factor.

Possible risk factors for extracranial germ cell tumors include:

• Having certain genetic syndromes:
  • Klinefelter syndrome may increase the risk of germ cell tumors in the mediastinum.
  • Swyer syndrome may increase the risk of gonadoblastoma and seminoma.
  • Turner syndrome may increase the risk of gonadoblastoma and dysgerminoma.
• Having an undescended testicle may increase the risk of testicular cancer.
• Having an ovary or testicle that has not formed normally (gonadal dysgenesis) may increase the risk of gonadoblastoma.

Talk with your child's doctor if you think your child may be at risk.

Signs of childhood extracranial germ cell tumors depend on where the tumor formed in the body.

Different tumors may cause the following signs and symptoms. Other conditions may cause these same signs and symptoms. It's important to check with your child's doctor if your child has:

• A lump in the neck, abdomen, or lower back.
• A painless lump in the testicle.
• Pain in the abdomen or back.
• Respiratory distress, chest pain, or cough.
• Fever.
• Constipation.
• Trouble urinating.
• Early puberty.
• In females, no menstrual periods or unusual vaginal bleeding.

Imaging studies and blood tests are used to diagnose childhood extracranial germ cell tumors.

If your child has symptoms that suggest they have an extracranial germ cell tumor, their doctor will need to find out if these are due to cancer or another problem. The doctor will ask when the symptoms started and how often your child has been having them. They will also ask about your child's personal and family medical history and do a physical exam. Depending on these results, they may recommend other tests. If your child is diagnosed with an extracranial germ cell tumor, the results of these tests will help you and your child's doctor plan treatment.

The tests used to diagnose extracranial germ cell tumors may include:

• 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.

  Some malignant germ cell tumors release tumor markers. The following tumor markers may be used to detect extracranial germ cell tumors:

  • Alpha-fetoprotein (AFP).
  • Beta-human chorionic gonadotropin (beta-hCG).
  For testicular germ cell tumors, blood levels of the tumor markers help show if the tumor is a seminoma or nonseminoma.
• 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, including lactate dehydrogenase. An unusual (higher or lower than normal) amount of a substance can be a sign of disease.
• 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, such as the chest or lymph nodes, 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. Sometimes an incisional biopsy or needle biopsy is done before surgery to remove a sample of tissue. Sometimes the tumor is removed during surgery and then a sample of tissue is removed from the tumor.

  The following tests may be done on the sample of tissue that is removed:

  • Cytogenetic analysis: A laboratory test in which the chromosomes of cells in a sample of tissue are counted and checked for any changes, such as broken, missing, rearranged, or extra chromosomes. Changes in certain chromosomes may be a sign of cancer. Cytogenetic analysis is used to help diagnose cancer, plan treatment, or find out how well treatment is working.
  • Immunohistochemistry: A laboratory test that uses antibodies to check for certain antigens (markers) in a sample of a patient's tissue. The antibodies are usually linked to an enzyme or a fluorescent dye. After the antibodies bind to a specific antigen in the tissue sample, the enzyme or dye is activated, and the antigen can then be seen under a microscope. This type of test is used to help diagnose cancer and to help tell one type of cancer from another type of cancer.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis and treatment options depend on the following:

• The child's age and general health.
• The stage of the cancer (whether it has spread to nearby areas, lymph nodes, or to other places in the body).
• Where the tumor first began to grow.
• The type of germ cell tumor.
• How well the tumor responds to treatment.
• Whether the child has gonadal dysgenesis.
• Whether the tumor can be completely removed by surgery.
• 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.