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What Are Germ Cell Tumors?
Germ cell tumors (GCTs) are growths or masses that form from germ cells in the reproductive organs and other body parts.
Germ cells are reproductive cells that normally develop into sperm in the testicles or unfertilized eggs in the ovaries of a fetus.
During your child’s fetal development, germ cells migrate through the body on their way to settling within the testicle or ovary. This means that while germ cell tumors are most common in the testicle or ovary, they can also occur elsewhere. They can form in the brain, central nervous system, chest, abdomen, or sacrum.
Tumors in reproductive organs are called gonadal tumors, while tumors in the brain are called intracranial. Germ cell tumors outside of these regions are called extracranial or extragonadal.
What are the types of germ cell tumors?
Germ cell tumors are classified based on their location in the body.
Germ cell tumors of the reproductive organs
These tumors include:
- Dysgerminomas – Tumors that form in the ovaries.
- Nonseminomatous germ cell tumors (NSGCTs) – A group of aggressive tumors. They include:
- Choriocarcinomas — Form in the ovaries, testicles, or other body parts. They make a hormone called beta-human chorionic gonadotropin (beta-hCG).
- Embryonal carcinomas — Form in the testicles or other body parts, but not in the ovaries. They may make beta-hCG.
- Gonadoblastomas — Form in the ovaries.
- Yolk sac tumors — Form in the ovaries, testicles, or other body parts. They make a hormone called alpha-fetoprotein (AFP). Usually cancerous, they spread quickly to lymph nodes and other organs. They are the most common cancerous germ cell tumors diagnosed in children.
- Seminomas – Tumors that form in the testicles.
Germ cell tumors of the central nervous system
Central nervous system germ cell tumors (CNS GCTs) are a group of brain tumors that grow from germ cells. These tumors vary in location. They occur most often in the first few months of life or between the ages of 10 and 19.
CNS GCTs sometimes occur along the spinal cord. Still, they are more commonly found within the brain. They may affect the pineal gland, basal ganglia, posterior lobe of the pituitary gland, or surrounding tissue.
CNS tumors include:
- Germinomas — Cancerous tumors that appear in the ovaries or testicles but are mostly found in the brain and spinal cord of the central nervous system. Dysgerminomas are germinomas in the ovaries; seminomas are germinomas in the testicles. Germinomas typically have good prognoses for treatment and recovery.
- Nongerminomas — Release identifying hormones that can show the presence of a tumor.
- Teratomas — These tumors may contain one or several different tissue types, such as hair, muscle, and bone. Mature teratomas, also called dermoid cysts, are usually benign. Immature teratomas are typically cancerous and grow very fast.
Mixed germ cell tumors
Mixed germ cell tumors comprise at least two types of malignant germ cells. They can form in the ovaries, testicles, or other body parts.
Most childhood extracranial germ cell tumors are mixed germ cell tumors. Their exact cause is unknown.
What is the difference between seminomas and nonseminomatous germ cell tumors?
Boys can have both seminomas and nonseminomas germ cell tumors. Both are malignant tumors of the testicles. While much more common in adulthood, they can also occur before then.
Seminomas often grow or spread more slowly than nonseminomas. Nonseminomas grow larger and spread more quickly.
How common are germ cell tumors?
Pediatric cancer is rare. Germ cell tumors are no different, accounting for about 3% of all childhood cancers.
Because these conditions are rare, it's recommended that you enroll your child in a clinical trial if one is available. These trials offer new therapies and techniques that might work better on germ cell tumors in children.
What causes germ cell tumors?
The direct cause of germ cell tumors is still unknown. However, the germ cells play a role in the development of these tumors. It can either occur when they migrate through the fetus during development or later in life in the reproductive organs.
All tumors occur due to a mutation or mistake in the gene sequence. This leads to the body producing unnecessary growths that can be cancerous.
Germ cell tumor risk factors
All tumors have the potential to cause major problems in the body, even if they're not cancerous.
Based on a tumor’s location, it may apply pressure on nearby organs as it grows larger. This pressure can make organs stop working and cause mild to major discomfort in your child.
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 a germ cell tumor. And tumors will develop in some children who have no known risk factors.
Germ cell tumors are more common in boys. They have a few risk factors that only apply to boys, including cryptorchidism (having an undescended testicle). Having a malformed ovary or testicle can also increase your child’s risk of a germ cell tumor.
Other syndromes can increase your child's risk, including:
- Klinefelter syndrome — Increases the risk of GCTs in the mediastinum.
- Swyer syndrome — Increases the risk of gonadoblastoma and seminoma.
- Turner syndrome — Increases the risk of gonadoblastoma and dysgerminoma.
Complications of germ cell tumors
If left untreated, germ cell tumors may grow and begin to affect the organs near them. This growth may lead to lumps forming on the affected body parts or complications with organ function.
Some germ cell tumors secrete reproductive hormones that cause atypical sexual development in children:
- Boys may have gynecomastia, which causes breast development.
- Girls may show signs of early puberty. They may develop breasts, grow pubic hair, or get their periods earlier than their peers.
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What Are the Signs and Symptoms of Germ Cell Tumors?
The signs and symptoms of childhood germ cell tumors depend on where the tumor forms in the body.
Germ cell tumors may cause some of the following signs and symptoms:
- Breast growth in boys.
- Early puberty.
- A lump in the neck, abdomen, or lower back.
- A lump in a testicle.
- Pain in the abdomen, back, or pelvis.
- Respiratory distress, chest pain, or cough.
- Swollen belly.
- Trouble peeing or pooping.
- Unusual vaginal bleeding in girls.
Other conditions can cause similar symptoms. It's important to check with your child's health care provider if they have any of these symptoms.
When should I see a doctor about my child's germ cell tumor symptoms?
If you notice any of the signs or symptoms listed above, you should see your child’s provider.
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How Do You Diagnose Germ Cell Tumors?
If your child has symptoms of a germ cell tumor, their provider will need to find out if they are due to cancer or another problem. They will ask you when the symptoms started and how often your child has had them. They'll also ask about your child's personal and family medical history and do a physical exam.
Depending on these results, your doctor may recommend other tests. If your child is diagnosed with a germ cell tumor, the results of these tests will help you and your child's doctor create a treatment plan.
You and your child might meet with different specialists as part of your child’s treatment plan.
These specialists could include:
You may also meet nurses, physician assistants, technicians, therapists, and other health professionals who help with your child's care.
Tests to diagnose germ cell tumors
If your child's provider suspects a germ cell tumor, they'll likely order blood tests and other diagnostic tests. The specific tests ordered depend on what part of the body the tumor is in.
The main procedures that can help diagnose germ cell tumors include:
- CT scan — A procedure that makes a series of detailed pictures of areas inside the body taken from different angles. A computer linked to an x-ray machine makes the pictures. Providers may inject a special dye into your child's vein or have them swallow it. The dye helps the organs or tissues show up more clearly.
- MRI — A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body.
- Neurological exam — This tests your child’s mental status and coordination, as well as their body’s reflexes and senses, to see if everything is functioning normally. The inability to score within the normal range could be a sign of tumor growth in the brain, spinal cord, or nerves.
- Paracentesis — If the abdomen is involved and there is extra fluid inside it, a paracentesis removes this fluid using a needle. This may help relieve symptoms. It allows the fluid to be tested under a microscope to look for cancer cells.
- PET scan — A procedure to check if there are rapidly dividing cells, such as cancer cells. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in areas affected by the cancer.
- Thoracentesis — If the thorax is involved and there is extra fluid inside it, a thoracentesis removes this fluid using a needle. This may help relieve symptoms. It allows the fluid to be tested under a microscope to look for cancer cells.
After a childhood germ cell tumor is diagnosed, more tests will take place. These tests can determine whether cancer cells have spread from the original tumor site to nearby tissues or other body parts.
Staging is the process of determining whether cancer has spread from its origin to other body parts. It describes the progression of the disease.
Knowing the stage is important for planning treatment. In some cases, staging may follow surgery to remove the tumor.
What is the survival rate for a child with a germ cell tumor?
Early-stage gonadal germ cell tumors generally have a very good survival rate. Early-stage gonadal GCTs have at least a 95% five-year survival rate. Advanced stages have at least an 85% five-year survival rate.
The lowest survival rates are for extragonadal GCTs in the mediastinum. The mediastinum is the center of the chest cavity between the lungs, containing the aorta, heart, esophagus, lymph nodes, nerves, thymus, and trachea. Extragonadal GCTs in the mediastinum have a four-year survival rate is 70%.
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How Do You Treat Germ Cell Tumors?
Treatment for germ cell tumors can include chemotherapy, radiation therapy, surgery, or a combination of them.
Surgery for germ cell tumors
Surgery is the main treatment for germ cell tumors.
The primary surgeries include:
Partial or complete oophorectomy
This procedure removes the part of the ovary that contains the tumor.
If the tumor is benign, a part of the ovary may be preserved. If the surgeons suspect the tumor is cancerous, they will likely remove the entire ovary. They'll also look at the other ovary to make sure it appears normal.
The fallopian tube may be preserved but could be removed if needed.
Radical inguinal orchiectomy
This procedure removes the involved testicle through an incision in the groin.
Tumor resection
This procedure removes the entire tumor. This may involve the removal of part of or the entire affected organ.
Sacrococcygeal teratoma
This typically involves removal of the entire tumor and the tip of the tailbone (the coccyx).
Chemotherapy for germ cell tumors
Chemotherapy involves a chemical treatment taken either by mouth or IV to stop cancer cells from dividing or kill them.
In some cases, doctors will use high doses of chemotherapy paired with stem cells to first eliminate the cancer cells and then provide healthy cells to encourage healing.
Radiation therapy for germ cell tumors
This procedure uses high-energy x-rays to target the tumor exactly where it is in the body. Radiation penetrates the body and destroys the cancer cells without damaging nearby tissues and organs.
Although radiation can cause side effects, it can be particularly effective on germ cell tumors that have regrown.
How effective is germ cell tumor treatment?
Your child's prognosis depends on the tumor location and stage.
How long does it take to recover after treatment for germ cell tumors?
Usually, children will have a short-term healing period of several weeks after surgery or chemotherapy. They'll also have long-term medical checkups that continue for at least five years.
Most children — especially those with tumors that have not spread — recover very well. Survival rates are above 90% for certain types like germinomas.
However, the length and difficulty of recovery can vary depending on:
- The tumor’s type.
- Where it's located.
- How intensive the treatment is.
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