Extracranial Germ Cell Tumor

What are extracranial germ cell tumors?

Childhood extracranial germ cell tumors form from developing sperm or egg cells that travel to parts of the body other than the brain. As a fetus develops, certain cells form sperm in the testicles or eggs in the ovaries. Sometimes these cells travel to other parts of the body and grow into germ cell tumors. This summary is about germ cell tumors that form in parts of the body that are extracranial (outside the brain). 

How common are extracranial germ cell tumors?

Extracranial germ cell tumors are most common in teenagers 15 to 19 years old.

What are the types of extracranial germ cell tumors?

There are three types of extracranial germ cell tumors. Extracranial germ cell tumors are grouped into:

• Mature teratomas. Mature teratomas are the most common type of extracranial germ cell tumor. The cells of mature teratomas look very much like normal cells. Mature teratomas are benign and not likely to become cancer. 
• Immature teratomas. Immature teratomas have cells that look very different from normal cells. Immature teratomas are not cancer. They often contain several different types of tissue such as hair, muscle, and bone. 
• Malignant germ cell tumors. Malignant germ cell tumors are cancer. There are three types of malignant germ cell tumors: 
  • Yolk sac tumors. Tumors that make a hormone called alpha-fetoprotein (AFP).
  • Germinomas. Tumors that make a hormone called beta-human chorionic gonadotropin (?-hCG).
  • Choriocarcinomas. Tumors that make a hormone called beta-human chorionic gonadotropin (?-hCG).

Childhood extracranial germ cell tumors are grouped as gonadal or extragonadal. Gonadal germ cell tumors form in the testicles or ovaries. Testicular germ cell tumors usually occur before the age of 4 years or in teenagers and young adults. Testicular germ cell tumors in teenagers and young adults are different from those that form in early childhood. They are more like testicular cancer in adults.

Seminoma. These tumors make a hormone called beta-human chorionic gonadotropin (?-hCG).

Nonseminoma. These tumors are usually large and cause symptoms. They tend to grow and spread more quickly than seminomas. Boys older than 14 years with testicular germ cell tumors are treated in pediatric cancer centers, but the treatment is similar to that used in adults. Ovarian germ cell tumors form in egg-making cells in an ovary. These tumors are more common in teenage girls and young women. Most ovarian germ cell tumors are benign teratomas. Extragonadal germ cell tumors form in areas other than the testicles or ovaries. Most germ cell tumors that are not in the testicles, ovaries, or brain, form along the midline of the body. This includes the following:

• Sacrum (the large, triangle-shaped bone in the lower spine that forms part of the pelvis)
• Coccyx (the small bone at the bottom of the spine, also called the tailbone)
• Mediastinum (the area between the lungs)
• Back of the abdomen
• Neck

In younger children, extragonadal extracranial germ cell tumors usually occur at birth or in early childhood. Most of these tumors are teratomas in the sacrum or coccyx. In older children, teenagers, and young adults, extragonadal extracranial germ cell tumors are often in the mediastinum. 

What causes extracranial germ cell tumors?

The cause of most childhood extracranial germ cell tumors is unknown. 

What are the risk factors for extracranial germ cell tumors?

Having certain inherited disorders can increase the risk of developing an extracranial germ cell tumor. Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Possible risk factors for extracranial germ cell tumors include the following: Having certain genetic syndromes may increase the risk of developing childhood germ cell tumors: 

• Klinefelter syndrome may increase the risk of developing germ cell tumors in the mediastinum
• Swyer syndrome may increase the risk of developing germ cell tumors in the testes or ovaries
• Having an undescended testicle may increase the risk of developing a testicular germ cell tumor.

Different tumors may cause the following signs and symptoms. Other conditions may cause these same symptoms. A doctor should be consulted if any of these problems occur.

• Most tumors of the sacrum and coccyx can be seen as a lump
• A testicular tumor may cause a painless lump in the testicles
• An ovarian germ cell tumor may cause
• Pain or a lump in the abdomen
• Fever
• Constipation
• No menstruation
• Unusual vaginal bleeding

What is the prognosis for children diagnosed with extracranial germ cell tumors?

The prognosis for childhood extracranial germ cell tumors, especially ovarian germ cell tumors, is good. The number of patients who have tumors that come back is small. Most recurrent germ cell tumors occur within three years of surgery. About half of the teratomas that recur in the sacrum or coccyx are malignant, so follow-up is important. The prognosis (chance of recovery) and treatment options depend on the following: 

• The type of germ cell tumor
• Where the tumor first began to grow
• The stage of the cancer (whether it has spread to nearby areas or to other places in the body)
• Whether the tumor can be completely removed by surgery
• The patient's age and general health
• Whether the cancer has just been diagnosed or has recurred (come back).

What are the stages of extracranial germ cell tumors?

In stage I, the cancer is found only in the testicle and is completely removed by surgery. Tumor marker levels return to normal after surgery.

In stage II, the cancer is removed by surgery and some cancer cells remain in the scrotum or cancer that can only be seen with a microscope has spread to the scrotum or spermatic cord. Tumor marker levels do not return to normal after surgery and may increase.

In stage III, the cancer has spread to one or more lymph nodes in the abdomen and is not completely removed by surgery. The cancer that remains after surgery can be seen without a microscope.

In stage IV, the cancer has spread to distant parts of the body such as the liver.

Recurrent childhood extracranial germ cell tumor is cancer that has recurred (come back) after it has been treated. The cancer may come back in the same place or in other parts of the body. 

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PDQ is the National Cancer Institute's (NCI's) comprehensive cancer information database. PDQ is provided as a service of the NCI. The NCI is part of the National Institutes of Health, the federal government's focal point for biomedical research. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. The PDQ cancer information summaries are developed by cancer experts and reviewed regularly.