A type of cell that forms as a fetus (also called an embryo) develops is called a germ cell. Germ cells are the cells that make the eggs (ova) in females and the sperm in males. Germ cell tumors (GCTs) are made up of these underdeveloped cells. These tumors are rare. They may be cancer (malignant) or not cancer (benign).

GCTs grow in these parts of the body:

• In the ovaries or testicles. Most GCTs start in the ovaries or testicles (testes). These are called gonadal tumors.
• Outside the ovaries or testicles. These tumors are called extragonadal tumors. They start in the cells that make up ovaries or testicles, but as a baby (fetus) develops, the cells travel to part of the body where they shouldn't be and grow there, like the following:
  • Brain (cranial)
  • Area between the lungs (mediastinal)
  • Back of the belly or abdomen (retroperitoneal)
  • Lower spine (sacrum and coccyx)
  • Head and neck

The tumors come in different types:

This group of GCTs includes all GCTs that don't form in the ovaries or testicles. Germinomas are the most common type of GCT that grows in the brain.

There are four types of nonseminoma germ cell tumors. This group of GCTs is also called nongerminomas.

• Endodermal sinus tumor (yolk sac tumor). This GCT is most often cancer (malignant) but may also be benign (not cancer). This tumor most often affects the ovaries or testes and the lower spine. They often grow fast. These make a hormone called AFP (alpha-fetoprotein).
• Choriocarcinoma. This kind of tumor is very rare. It's most often malignant. It starts from a layer of the placenta. During pregnancy it may spread (metastasize) to the baby and mother. When this happens, it's called gestational choriocarcinoma. It most often occurs in young pregnant people. It makes a hormone called beta-hCG (beta-human chorionic gonadotropin). A choriocarcinoma can also form in a young child. It starts in chorion cells that are still in the child's body. This is called nongestational choriocarcinoma.
• Embryonal carcinoma. This type of tumor is usually malignant. It can spread quickly. It doesn't grow in the ovaries. It most often forms in the testes, and can form in other parts of the body, too.
• Gonadoblastoma. Almost all these benign tumors form in the ovaries. If not treated, over time they can become cancer.

Many germ cell tumors have more than one type of malignant (cancer) cell in them. These tumors are treated based on the cell type that is most common. They can form anywhere in the body.

These tumors contain several types of tissue. They can be either mature teratomas, which are mostly benign or immature teratomas, which are often malignant. They're the most common germ cell tumor in the ovaries. Sometimes teratomas make enzymes or hormones that cause problems.

The cause of germ cell tumors isn't fully known. Some gene defects passed on from parents to children (inherited mutations) may increase the risk for germ cell tumors. Some genetic syndromes, like Turner syndrome, androgen insensitivity syndrome, and Klinefelter syndrome, are linked to a higher risk for these tumors. GCTs are also linked to abnormal development of the male and female reproductive systems. Male children born with undescended testicles (called cryptorchidism) are at higher risk for germ cell tumors in the testicles.

Symptoms depend on the size of the tumor and where it is in the body. Symptoms can also depend on whether the tumor is making hormones. They can include:

• A lump or mass that can be felt or seen.
• Belly (abdominal) pain.
• Chest pain.
• Trouble breathing.
• A cough.
• Trouble with eyesight.
• A fever.
• Pain in the lower spine.
• The need to urinate often or trouble urinating.
• Trouble with bowel movements (constipation).
• Increased thirst and urination.
• Loss of appetite.
• Increased hair growth.
• Vaginal bleeding.
• No menstrual periods.
• Early puberty.
• Being shorter than normal.
• An abnormal shape or size of testicles.
• Weight loss with no known reason for it.
• Nausea, vomiting, or both.

The symptoms of germ cell tumors can be a lot like those of many other health conditions. Make sure your child sees a doctor for a diagnosis.

The doctor will ask questions about your child's medical history and current symptoms. A physical exam will be done, and close attention will be paid to areas with lumps, pain, or other symptoms. Your child may need to see a cancer specialist (pediatric oncologist). Your child may need certain tests. The tests done depend on where the tumor is and can include:

• Blood tests. These tests check for signs of disease, look at liver and kidney functions, measure hormone levels, and look for tumor cell markers (such as AFP and beta hCG).
• Biopsy. A tiny piece (called a sample) of tissue is removed from the tumor and tested for cancer cells. This can be done during surgery or by using a needle to take out a sample. A biopsy is the only way to know for sure if the tumor is or isn't cancer.
• CT scan. A series of X-rays taken from different angles and a computer are used to make 3-D images of the inside of the body.
• MRI. Large powerful magnets, radio waves, and a computer are used to make detailed images of the inside of the body.
• X-ray. A small amount of radiation is used to make images of internal tissues, bones, and organs.
• Ultrasound (sonography). Sound waves and a computer are used to create images of blood vessels, tissues, and organs.

After a diagnosis of germ cell tumor, your child will need more tests. These help doctors learn more about your child's overall health and the tumor. They're used to find out the stage of the cancer. The stage is how much cancer there is and how far it has spread (metastasized) in your child's body. A stage grouping is then assigned. In some cases, a stage grouping isn't assigned until after surgery is done to remove the tumor.

Stage groupings give an overall description of the cancer. A stage grouping is listed as a Roman numeral and can have a value of I (1), II (2), III (3), or IV (4). The higher the number, the more advanced the tumor is. Letters and numbers can be used after the Roman numeral to give more details.

The stage of a cancer is one of the most important things to know when deciding how to treat the cancer. Be sure to ask your child's doctor to explain the details of your child's cancer to you in a way you can understand.

Your child may be treated by a team made up of several types of doctors. Treatment choices depend on things like the type of germ cell tumor and where it is. GCTs can be treated with any of these:

• Surgery. This is done to take out the tumor and an edge of nearby normal tissue (surgical margin). The organ where the tumor is growing may also be removed. For instance, this may be an ovary or testicle.
• Chemotherapy. These are strong medicines that kill cancer cells. They may be given by mouth, right into the blood through a vein (IV), or in other ways.
• Radiation therapy. These are high-energy X-rays or other types of radiation. Radiation is used to kill cancer cells or stop them from growing.
• High-dose chemotherapy with a stem cell transplant. Young blood cells (called stem cells) are taken from the child or from someone else (a donor). Then high doses of chemotherapy are given to your child. This kills the cancer cells but also causes bone marrow damage and kills stem cells. After the chemotherapy, the stem cells are put back into your child's blood. Over time, they rebuild the bone marrow.
• Clinical trials. Ask your child's doctor if there are any treatments being tested that may work well for your child. This allows your child to get the best treatment available today, and may also be the treatment that's thought to be even better.
• Supportive care. Treatment can cause side effects. Medicines and other treatments can be used for things like pain, fever, infection, and nausea and vomiting. Managing side effects is a key part of good cancer treatment.

With any cancer, how well a child is expected to recover (their prognosis) varies. Keep in mind:

• Getting medical treatment right away is important for the best prognosis. Cancer that has spread is harder to treat.
• Ongoing follow-up care during and after treatment is needed.
• New treatments are being tested to improve outcomes and to reduce side effects.

Talk with your child's doctors about treatment choices. Make a list of questions. Think about the benefits and possible side effects of each choice. Talk about your concerns with your doctor before making a decision.

A child may have complications from the tumor or from treatment. Many are short-term and will go away after treatment ends. But some problems might be long-term and affect your child the rest of their life.

Side effects and some complications may include:

• Damage to the brain or nervous system that causes problems with coordination, muscle strength, speech, or eyesight.
• Loss of appetite.
• Infection.
• Bleeding.
• Tiredness that doesn't get better with rest (fatigue).
• Hair loss.
• Nausea and vomiting.
• Mouth sores.
• Delayed growth and development.
• Learning problems.
• Problems with reproduction (infertility).
• Return of the cancer.
• Growth of other cancers later in life.

Talk with your child's doctors about side effects linked with your child's treatment. There are often ways to manage them. There may be things you can do and medicines you can give your child to help prevent or control many treatment side effects.

A child with a germ cell tumor needs ongoing care. Your child will be seen by oncologists and other health care providers to treat any late effects of treatment and to watch for signs or symptoms of the tumor returning. Your child will be checked with imaging tests and other tests. And your child may see other health care providers for problems caused by the tumor or treatment.

You can help your child manage their treatment in many ways. For example:

• Your child may have trouble eating. A dietitian may be able to help.
• Your child may be very tired. They will need to balance rest and activity. Encourage your child to get some exercise. This is good for overall health. And it may help to reduce tiredness. Ask your child's doctor what types of exercise are safe for your child.
• Get emotional support for your child. Find a counselor or a child support group that can help.
• Make sure your child attends all follow-up appointments.

Contact the doctor if your child has:

• Symptoms that get worse.
• New symptoms.
• Signs of infection, such as fever.
• Side effects that don't get better with treatment.

Ask your child's doctor what signs to watch for and when to call. Know how to get help after office hours and on weekends and holidays.

• Germ cell tumors may be cancer (malignant) or not cancer (benign).
• The tumors usually affect the ovaries or testicles. They may also affect the brain, mediastinum, retroperitoneum, sacrum, or coccyx.
• Symptoms depend on the size of the tumor and where it is in your child's body. There may be a lump, pain, or other symptoms.
• Germ cell tumors are diagnosed with blood tests, a biopsy, and imaging tests.
• Treatment may include surgery, chemotherapy, and radiation therapy.

Tips to help you get the most from a visit to your child's doctor:

• Know the reason for the visit and what you want to happen.
• Before your visit, write down questions you want answered.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions the doctor gives you for your child.
• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are and when they should be reported.
• Ask if your child's condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if your child does not take the medicine or have the test or procedure.
• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your child's doctor after office hours and on weekends and holidays. This is important if your child becomes ill and you have questions or need advice.