Germ Cell Tumors
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What are germ cell tumors?
Germ cell tumors are malignant (cancerous) or nonmalignant (benign, noncancerous)
tumors that are comprised mostly of germ cells. Germ cells are the cells that develop
in the embryo (fetus, or unborn baby) and become the cells that make up the reproductive
system in males and females. These germ cells follow a midline path through the body
after development and descend into the pelvis as ovarian cells or into the scrotal
sac as testicular cells. Most ovarian tumors and testicular tumors are of germ cell
origin. The ovaries and testes are called gonads.
Tumor sites outside the gonad are called extragonadal sites. The tumors also occur
along the midline path and can be found in the head, chest, abdomen, pelvis, and sacrococcygeal
(lower back) area.
Germ cell tumors are rare. Germ cell tumors account for about 2 to 4 percent of all
cancers in children and adolescents younger than age 20.
Germ cell tumors can spread (metastasize) to other parts of the body. The most common
sites for metastasis are the lungs, liver, lymph nodes, and central nervous system.
Rarely, germ cell tumors can spread to the bone, bone marrow, and other organs.
What causes germ cell tumors?
The cause of germ cell tumors isn't completely understood. A number of inherited defects
have also been associated with an increased risk for developing germ cell tumors including
the central nervous system and genitourinary tract malformations and major malformations
of the lower spine. Specifically, males with cryptorchidism (failure of the testes
to descend into the scrotal sac) have an increased risk to develop testicular germ
cell tumors. Cryptorchidism can occur alone, however, and is also present in some
Some genetic syndromes caused by extra or missing sex chromosomes can cause incomplete
or abnormal development of the reproductive system.
What are the symptoms of germ cell tumors?
The following are the most common symptoms of germ cell tumors. However, each child
may experience symptoms differently. Symptoms vary depending on the size and location
of the tumor. Symptoms may include:
A tumor, swelling, or mass that can be felt or seen
Elevated levels of alpha-fetoprotein (AFP)
Elevated levels of beta-human chorionic gonadotropin (ß-HCG)
Constipation, incontinence, and leg weakness can occur if the tumor is in the sacrum
(a segment of the vertebral column that forms the top part of the pelvis) compressing
Abnormal shape, or irregularity in, testicular size
Shortness of breath or wheezing if tumors in the chest are pressing on the lungs
The symptoms of germ cell tumors may resemble other conditions or medical problems.
Always consult your child's doctor for a diagnosis.
How are germ cell tumors diagnosed?
In addition to a complete medical history and physical examination, diagnostic procedures
for germ cell tumors may include:
Biopsy. A sample of tissue is removed from the tumor and examined under a microscope.
Complete blood count (CBC). This measures size, number, and maturity of different blood cells in a specific volume
Additional blood tests. These tests may include blood chemistries, evaluation of liver and kidney functions,
tumor cell markers, and genetic studies.
Multiple imaging studies, including:
Computed tomography (CT) scan. This is a diagnostic imaging procedure that uses a combination of X-rays and computer
technology to produce horizontal, or axial, images (often called slices) of the body.
A CT scan shows detailed images of any part of the body, including the bones, muscles,
fat, and organs. CT scans are more detailed than general X-rays.
Magnetic resonance imaging (MRI). This is a diagnostic procedure that uses a combination of large magnets, radio frequencies,
and a computer to produce detailed images of organs and structures within the body,
without the use of X-rays.
X-ray. This diagnostic test uses invisible electromagnetic energy beams to produce images
of internal tissues, bones, and organs onto film.
Ultrasound (also called sonography). This is a diagnostic imaging technique that uses high-frequency sound waves and a
computer to create images of blood vessels, tissues, and organs. Ultrasounds are used
to view internal organs as they function, and to assess blood flow through various
Bone scans. This involves pictures or X-rays taken of the bone after a dye has been injected that's
absorbed by bone tissue. These are used to detect tumors and bone abnormalities.
What are the different types of germ cells?
Diagnosis of germ cell tumors depends on the types of cells involved. The most common
types of germ cell tumors include:
Teratomas. Teratomas contain cells from the three germ layers: ectoderm, mesoderm, and endoderm.
Teratomas can be malignant or benign, depending on the maturity and other types of
cells that may be involved. Teratomas are the most common germ cell tumor found in
the ovaries. Sacrococcygeal (tail bone, or distal end of spinal column) teratomas
are the most common germ cell tumors found in childhood. Because these sacrococcygeal
tumors are often visible from the outside of the body, diagnosis is made early and
treatment and/or surgery are initiated early, making the prognosis for this type of
germ cell tumor very favorable.
Germinomas. Germinomas are malignant germ cell tumors. Germinomas are also termed dysgerminoma
when located in the ovaries; and seminoma when located in the testes. Among children,
germinoma, or dysgerminoma, occurs most frequently in the ovary of a prepubescent
or adolescent female. Dysgerminoma is the most common malignant ovarian germ cell
tumor seen in children and adolescents.
Endodermal sinus tumor or yolk sac tumors. Endodermal sinus tumor or yolk sac tumors are germ cell tumors that are most often
malignant, but may also be benign. These tumors are most commonly found in the ovary,
testes, and sacrococcygeal areas (tail bone, or distal end of spinal column). When
found in the ovaries and testes, they're often very aggressive, malignant, and can
spread rapidly through the lymphatic system and other organs in the body. Most yolk
sac tumors will require surgery and chemotherapy, regardless of stage or presence
of metastasis, because of the aggressive nature and recurrence of the disease.
Choriocarcinoma. Choriocarcinoma is a very rare, but often malignant germ cell tumor that arises
from the cells in the chorion layer of the placenta (during pregnancy, a blood-rich
structure through which the fetus takes in oxygen, food, and other substances while
getting rid of waste products). These cells may form a tumor in the placental cells
during pregnancy and spread (metastasize) to the infant and mother. When the tumor
develops during pregnancy, it's called gestational choriocarcinoma. Gestational choriocarcinoma
most often occurs in pregnant females who are between ages 15 and 19. If a nonpregnant
young child develops choriocarcinoma from the chorion cells that originated from the
placenta that are still in the body, the term used is nongestational choriocarcinoma.
Embryonal carcinoma. Embryonal carcinoma cells are malignant cells that are usually mixed with other types
of germ cell tumors. They occur most often in the testes. These types of cells have
the ability to rapidly spread to other parts of the body. When these cells are mixed
with an otherwise benign type of tumor (mature teratoma), the presence of embryonal
carcinoma cells will cause it to become malignant (cancerous).
Many germ cell tumors have multiple types of cells involved. The diagnosis, treatment,
and prognosis are based on the most malignant of the cells present and the majority
type of cells that are present.
What is the treatment for germ cell tumors?
Specific treatment for germ cell tumors will be determined by your child's doctor
Your child's age, overall health, and medical history
Extent of the disease
Your child's tolerance for specific medications, procedures, or therapies
Expectations for the course of the disease
Your opinion or preference
Treatment may include (alone or in combination):
Surgery (to remove the tumor and involved organs)
Bone marrow transplantation
Supportive care (for the effects of treatment)
Hormonal replacement (if necessary)
Antibiotics (to prevent or treat infections)
Continuous follow-up care (to determine response to treatment, detect recurrent disease,
and manage the late effects of treatment)
What is the long-term outlook of a child with a germ cell tumor?
Prognosis greatly depends on:
The extent of the disease
The size and location of the tumor
Presence or absence of metastasis
The tumor's response to therapy
The age and overall health of your child
Your child's tolerance of specific medications, procedures, or therapies
New developments in treatment
As with any cancer, prognosis and long-term survival can vary greatly from individual
to individual. Prompt medical attention and aggressive therapy are important for the
best prognosis. Continuous follow-up care is essential for a child diagnosed with
a germ cell tumor. Side effects of radiation and chemotherapy, as well as second malignancies,
can occur in survivors of germ cell tumors. New methods are continually being discovered
to improve treatment and to decrease side effects.
Online Medical Reviewers:
- Bass, Pat F. III, MD, MPH
- MMI board-certified, academically affiliated clinician