What Is It?
Extragonadal germ cell tumors are made up of cells that form during the early development of a fetus (unborn baby). In a growing fetus, germ cells typically move from a site near the middle of the body to the ovaries or testes (gonads). There they develop into eggs in females and sperm in males.
When cells that are meant to form sperm or eggs travel to other parts of the body instead, they can form tumors outside the gonads. That's why they are often called extragonadal germ cell tumors. They usually begin in the lungs; the lower back; the back of the abdomen; or the middle of the brain, near the pea-sized pineal gland.
Extragonadal germ cell tumors (EGCTs) are rare. EGCTs are classified as seminomas or nonseminomas (of which there are several subtypes). In children, EGCTs affect boys and girls equally. But in adults, the vast majority of these tumors affect men.
The cells of each type of tumor look different under a microscope. Also, each has a different prognosis and treatment. Seminomas tend to be very responsive to radiation therapy, making that the mainstay for treatment. Chemotherapy is often used to treat nonseminomas, but it may be used to treat seminomas as well.
This article will focus on seminomas and nonseminomas.
Symptoms depend on the location of the tumor:
A child with a tumor that produces hormones may show signs of puberty earlier than normal. Almost all pineal germ cell tumors, which are very rare, occur in people younger than 40.
Because EGCTs are rare, your doctor probably will ask about common medical conditions that could be causing your symptoms. For example, if you have a cough, fever and difficulty breathing, your doctor may suspect a respiratory infection. The true cause of your condition probably won't be known until your doctor orders X-rays or scans of the area where you have symptoms.
Your doctor will examine you, paying special attention to the area where you have symptoms. If you have symptoms of a lower-back tumor, your doctor may do a rectal exam and, in women, a pelvic exam. If you have symptoms of a brain tumor, he or she will do a neurological exam.
Your doctor will order different diagnostic tests depending on the tumor's location:
Because of the association between EGCTs and a rare blood cancer, your doctor may check your blood counts. An evaluation of your bone marrow may also be part of the diagnostic workup.
In most patients, blood tests of the levels of AFP and beta-hCG can help to determine the type of tumor (seminoma or nonseminoma). In people with brain (pineal) tumors, AFP and beta-hCG levels also may be measured in the spinal fluid. The fluid is removed from the spinal cord with a needle. This procedure is called a spinal tap (lumbar puncture).
Unless treated, an EGCT will continue to grow. Depending on its location, the cancer may spread to the lungs, bones (especially the spine), liver or other sites.
There is no way to prevent EGCTs.
Treatment depends on the location and type of tumor. In general, small seminomas are treated with radiation; larger ones are treated with chemotherapy (anticancer drugs) followed by radiation. Nonseminomas almost always are treated with chemotherapy followed by surgery to remove any remaining cancer. Some medical centers also use high-dose chemotherapy with a bone marrow or stem cell transplant.
Because doctors want to determine the best treatment for rare cancers, your doctor may talk with you about enrolling in a clinical trial. Clinical trials study experimental drugs and other new therapies.
When To Call a Professional
Call your doctor if you or your child has any symptoms of an EGCT. Because these tumors are rare, many cancer specialists have limited experience in treating them. If you are diagnosed with one of these tumors, get a second opinion. Seek treatment at a cancer center with staff experienced in treating these tumors.
Survival for people with EGCTs depends on the tumors' location:
National Cancer Institute (NCI)
NCI Office of Communications and Education
Public Inquiries Office
6116 Executive Boulevard
Bethesda, MD 20892-8322
American Cancer Society (ACS)
American College of Obstetricians and Gynecologists
P.O. Box 96920
Washington, DC 20090-6920