Definition of extracranial germ cell tumour:
A rare cancer that forms in germ cells in the testicle or ovary, or in germ cells that have traveled to areas of the body other than the brain (such as the chest, abdomen, or tailbone). Germ cells are reproductive cells that develop into sperm in males and eggs in females.
Childhood extracranial germ cell tumours form from developing sperm or egg cells that travel to parts of the body other than the brain.
As a fetus develops, certain cells form sperm in the testicles or eggs in the ovaries. Sometimes these cells travel to other parts of the body and grow into germ cell tumours. This summary is about germ cell tumours that form in parts of the body that are extracranial (outside the brain). Extracranial germ cell tumours are most common in teenagers 15 to 19 years old.
Childhood extracranial germ cell tumours may be benign or malignant.
Extracranial germ cell tumours may be benign (noncancer) or malignant (cancer).
There are three types of extracranial germ cell tumours.
Extracranial germ cell tumours are grouped into mature teratomas, immature teratomas, or malignant germ cell tumours:
Mature teratomas are the most common type of extracranial germ cell tumour. The cells of mature teratomas look very much like normal cells. Mature teratomas are benign and not likely to become cancer.
Immature teratomas have cells that look very different from normal cells. Immature teratomas are not cancer. They often contain several different types of tissue such as hair, muscle, and bone.
Malignant Germ Cell tumours
Malignant germ cell tumours are cancer. There are three types of malignant germ cell tumours:
- Yolk sac tumours (endodermal sinus tumour): tumours that make a hormone called alpha-fetoprotein (AFP).
- Germinomas: tumours that make a hormone called beta-human chorionic gonadotropin (β-hCG).
- Choriocarcinomas: tumours that make a hormone called beta-human chorionic gonadotropin (β-hCG).
Childhood extracranial germ cell tumours are grouped as gonadal or extragonadal.
Malignant extracranial germ cell tumours are grouped into gonadal and extragonadal.
Gonadal Germ Cell tumours
Gonadal germ cell tumours form in the testicles or ovaries.
Testicular Germ Cell tumours
Testicular germ cell tumours usually occur before the age of 4 years or in teenagers and young adults.
Testicular germ cell tumours in teenagers and young adults are different from those that form in early childhood. They are more like testicular cancer in adults. Testicular germ cell tumours are divided into two main types, seminoma and nonseminoma. (See the summary on Testicular Cancer in the A-Z List of Cancers for more information.)
- Seminoma: These tumours make a hormone called beta-human chorionic gonadotropin (β-hCG).
- Nonseminoma: These tumours are usually large and cause symptoms. They tend to grow and spread more quickly than seminomas.
Boys older than 14 years with testicular germ cell tumours are treated in pediatric cancer centers, but the treatment is similar to that used in adults. (See the summary on Testicular Cancer in the A-Z List of Cancers for more information here.)
Ovarian Germ Cell tumours
Ovarian germ cell tumours form in egg-making cells in an ovary. These tumours are more common in teenage girls and young women. Most ovarian germ cell tumours are benign teratomas. (See the summary on Ovarian Germ Cell tumours in the A-Z List of Cancers for more information here.)
Extragonadal Extracranial Germ Cell tumours
Extragonadal germ cell tumours form in areas other than the testicles or ovaries.
Most germ cell tumours that are not in the testicles, ovaries, or brain, 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 tumours usually occur at birth or in early childhood. Most of these tumours are teratomas in the sacrum or coccyx.
In older children, teenagers, and young adults, extragonadal extracranial germ cell tumours are often in the mediastinum.
The cause of most childhood extracranial germ cell tumours is unknown.
Having certain inherited disorders can increase the risk of developing an extracranial germ cell tumour.
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 tumours include the following:
- Having certain genetic syndromes may increase the risk of developing childhood germ cell tumours:
- Klinefelter syndrome may increase the risk of developing germ cell tumours in the mediastinum.
- Swyer syndrome may increase the risk of developing germ cell tumours in the testes or ovaries.
- Having an undescended testicle may increase the risk of developing a testicular germ cell tumour.
Signs of childhood extracranial germ cell tumours depend on the type of tumour and where it is in the body.
Different tumours may cause the following signs and symptoms. Other conditions may cause these same symptoms. Check with a doctor if your child has any of the following problems:
- Most tumours of the sacrum and coccyx can be seen as a lump.
- A testicular tumour may cause a painless lump in the testicles.
- An ovarian germ cell tumour may cause:
- Pain or a lump in the abdomen.
- No menstruation.
- Unusual vaginal bleeding.
Imaging studies and blood tests are used to detect (find) and diagnose childhood extracranial germ cell tumours.
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 tumour 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 tumour cells in the body. Certain substances are linked to specific types of cancer when found in increased levels in the blood. These are called tumour markers.
Most malignant germ cell tumours release tumour markers. The following tumour markers are used to detect extracranial germ cell tumours:
- Alpha-fetoprotein (AFP).
- Beta-human chorionic gonadotropin (β-hCG).
For testicular germ cell tumours, blood levels of the tumour markers help show if the tumour 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. 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.
- 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 study: A laboratory test in which a substance such as an antibody, dye, or radioisotope is added to a sample of cancer tissue to test for certain antigens. This type of study is used to tell the difference between different types of cancer.
- 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.
- 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 tumour is removed during surgery and then a biopsy is done.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options depend on the following:
- The type of germ cell tumour.
- Where the tumour 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 tumour 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 tumours, especially ovarian germ cell tumours, is good.
For more information on Extracranial Germ Cell tumour (Childhood) click here
This link is to the National Cancer Institute (NCI) cancer website in the United States. There may be references to drugs and clinical trials that are not available here in Australia.