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Doctors use many tests to diagnose a germ cell tumor and find out if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of tumors, a biopsy is the only way to make a definitive diagnosis. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the tumor has metastasized. Your child’s doctor may consider these factors when choosing a diagnostic test:
- Age and medical condition
- Type of tumor suspected
- Severity of symptoms
- Previous test results
In addition to a physical examination, the following tests may be used to diagnose a germ cell tumor:
Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that a germ cell tumor is present, but only a biopsy can make a definite diagnosis and determine if the tumor is benign or cancerous. The sample removed from the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease). The pathologist will examine the tissue sample for abnormalities in the cells (called a histologic examination) and for signs of cancer (called a cytologic examination).
Blood tests/alphafetoprotein (AFP). A germ cell tumor may cause high levels of AFP, which is a protein that increases in the mother’s blood during pregnancy and can be detected by amniocentesis (a test used to monitor the health of a fetus by using a needle inserted into the abdomen and uterus of a pregnant woman to collect amniotic fluid). AFP is also a tumor marker in patients with certain germ cell tumors. A tumor marker is a substance found in higher than normal amounts in the blood, urine, or body of people with certain kinds of tumors. The levels of AFP in the blood may be monitored to determine how well a treatment is working.
A germ cell tumor may also cause high levels of beta human chorionic gonadotropin (hCG). Women who are pregnant produce high levels of the hormone beta hCG in their blood. High levels of beta hCG in a woman who is not pregnant could mean that a germ cell tumor is present.
Ultrasound. An ultrasound uses sound waves to create a picture of the internal organs. A tumor produces different echoes of the sound waves than normal tissue. When the sound waves are bounced back to a computer, creating images, the doctor can locate a mass inside the body.
Computed tomography (CT or CAT) scan. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail.
Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient’s vein to create a clearer picture.
Learn more about what to expect when having common tests, procedures, and scans.
After these diagnostic tests are done, your child’s doctor will review all of the results with you. If a germ cell tumor is diagnosed, these results also help the doctor describe the tumor; this is called staging. Learn more about the first steps to take after a diagnosis of a tumor.