What are Germ Cell Tumors?
Germ cell tumors are solid tumors that begin in a cell that is destined to become a reproductive cell; in other words, an egg or a sperm. Gonadal germ cell tumors (GCTs) are most commonly present in the testis of a male or the ovary of a female. When GCTs appear in other areas of the body, they are referred to as extragonadal. If they occur primarily in the brain, they are called intracranial GCTs. Because a normal germ cell has the potential to create a whole living being, the cell of a germ cell tumor has the potential to represent different tissues of the body.
Germ cell tumors can be benign, such as teratomas or dermoid tumors, and may contain tissue representing fat, hair, teeth, cartilage, nerve tissue, and glands in various stages of development. Malignant germ cell tumors carry different names based on the type of cells that are most representative of the tumor. The most common malignant germ cell tumor of childhood is a yolk sac tumor, which produces the blood marker alpha fetoprotein (AFP). Most tumors have a mixed representation of cells, including yolk sac components, as well as seminoma (testis), dysgerminoma (ovary), embryonal carcinoma, and both immature and mature teratoma elements.
Although the cause of most germ cell tumors is unknown, there are several well-appreciated risk factors that share a common theme of impaired development of the sex determining organs. They are:
- Boys who have undescended testis (known as cryptorchidism).
- Male patients who are genetically resistant to male hormones and appear to be female.
- Disorders of the normal sex chromosome number (XX for female and XY for males) are also associated with the development of germ cell tumors. These include single X females (Turner Syndrome) and XXY males (Klinefelter Syndrome).
Germ cell tumors most commonly affect adolescents and young adults, but they can occur at any age.
However, infants may be born with a mass in the midline of their body since that is the path taken by a germ cell in the fetus. These congenital masses most often begin in the coccyx or behind the breast bone.
Germ cell tumors are among the most curable pediatric tumors, therefore the focus is on curing the cancer with the least amount of therapy possible to reduce short- and long-term side effects.
Symptoms may include:
- Painless swelling of the testicle or abdomen.
- If the testicle or ovary gets large enough, it may twist on itself and cut off its own blood supply (known as torsion), causing sudden onset pain.
- Tumors arising in the chest may cause shortness of breath.
- Tumors in the brain may cause unusual thirst, frequent urination, early onset puberty, or changes in vision.
We diagnose germ cell tumors with various tests, including:
- Measuring blood levels of the pregnancy hormone BhCG or AFP. Since germ cell tumors can be hormonally active, these hormone levels may be elevated and indicate this condition.
- Imaging tests such as an ultrasound, CT scan, and MRI.
Treatment may include:
- Radiation for primarily for intracranial tumors