A germ cell tumor is a benign (noncancerous) or malignant (cancerous) mass that forms from germ cells. Most tumors appear in your ovaries or testicles, but they can occur in other body parts, too, including your chest, tailbone and brain. Germ cell tumors can affect anyone, but they’re most common in children, teens and young adults.
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A germ cell tumor is a mass made of reproductive cells, also called germ cells. “Germ” is short for “germinate,” which means to mature. For women and people assigned female at birth (AFAB), germ cells eventually mature into eggs. For men and people assigned male at birth (AMAB), germ cells mature into sperm. Related, germ cell tumors most often form where eggs get made (ovaries) and where sperm gets made (testicles).
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Less commonly, germ cell tumors form in body parts other than your ovaries and testicles, including your abdomen, chest, low back, tailbone and brain. These tumors are called extragonadal tumors.
Germ cell tumors most commonly affect children, teens and young adults.
Germ cell tumors may be malignant (cancerous) or benign (noncancerous). Both types of tumors can grow larger, but only cancerous germ cell tumors can spread to other parts of your body. Cancer that’s spread (metastasized) can damage your organs and is more difficult to treat.
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Germ cell tumors affecting men and people AMAB are classified as either seminomas or non-seminomas. Both are malignant tumors that may affect your testicles (testicular cancer).
Germ cell tumors in children are rare, making up only 3.5% of cancer diagnoses. They’re more common in adolescents and young adults, making up 13.9% of cancers diagnosed between ages 15 to 19.
Anyone can have germ cell tumors, but infants, children, teens and young adults get them most often. Diagnoses increase and decrease based on age. For instance, diagnoses occur relatively frequently from infancy up to age 4 compared to the years immediately after. Germ cell tumor diagnoses increase as puberty approaches.
The symptoms of a germ cell tumor depend on factors like the tumor’s size and location in your body.
Ovarian germ cell tumors don’t always cause symptoms. For instance, mature teratomas may not cause symptoms until they’ve grown large enough to create pressure in your abdomen. Often, they’re discovered on an ultrasound to determine what’s causing pelvic pain.
Symptoms may include:
The symptoms of testicular germ cell tumors are the same as those of testicular cancer.
Symptoms include:
A mass on your child’s tailbone or in the center of their chest may signify a teratoma. Other symptoms of an extragonadal germ cell tumor depend on the tumor’s location.
Some germ cell tumors secrete reproductive hormones that may cause symptoms of early puberty or atypical sexual development in children. People AFAB may develop breasts, grow pubic hair and get their periods early. People AMAB may grow breasts (gynecomastia).
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Normal germ cells form in a developing human embryo. These cells eventually travel to the embryo’s ovaries or testicles, becoming egg cells or sperm cells.
In contrast, germ cell tumors consist of cells that don’t develop into fully formed eggs or sperm. The germ cells divide abnormally and become a tumor in your ovaries or testicles instead. In the case of extragonadal tumors, the germ cells travel to odd places in your body — like your chest, brain, belly, low back and tailbone — to form tumors.
Researchers aren’t sure what causes germ cells to develop this way.
You may be more likely to get a germ cell tumor if you have a family history of germ cell tumors or a history of certain conditions.
These include:
Your healthcare provider will perform a physical exam and ask about symptoms. They may perform any of the following tests or procedures to diagnose a germ cell tumor:
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Your provider may remove the affected organ if your tumor’s likely malignant. For instance, removing your entire testicle (radical inguinal orchiectomy) is a standard part of a testicular cancer diagnosis. Removing your testicle allows your provider to analyze the tissue and provide treatment (surgery).
The prognosis for most germ cell tumors is excellent. Removing the tumor completely often cures the disease. For instance, testicular cancer has a 95% survival rate following treatment. Ovarian germ cell tumors have a 93% survival rate. The cure rate for children with germ cell tumors ranges from 82% to 90%.
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Still, likely outcomes depend on various factors unique to you, including:
Talk to your healthcare provider about how your diagnosis will affect your outcomes.
Questions that you can ask to better understand your diagnosis include:
A note from Cleveland Clinic
A germ cell tumor is a mass made of reproductive cells, also called germ cells. Your healthcare provider can explain what a germ cell tumor diagnosis means for you or your child. Germ cell tumors are complex. The symptoms you experience and your likely prognosis all depend on various factors that your provider can discuss with you. Luckily, most germ cell tumors respond well to treatment. As with any other tumor diagnosis (especially malignant tumors), the earlier you’re diagnosed and begin treatment, the better your outcome will likely be.
Last reviewed on 07/15/2022.
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