What Causes Childhood Extracranial Germ Cell Tumors?

What are childhood extracranial germ cell tumors?

Childhood extracranial germ cell tumors form from germ cells that travel to parts of the body other than the brain.

Germ cells are cells that form from reproductive cells, later becoming sperm cells in males and eggs in females. Tumors may form in these germ cells before or after birth and may be benign (noncancerous) or malignant.

Extracranial germ cell tumors occur mostly in the following areas of the body:

• Testicles
• Ovaries
• Neck
• Mediastinum (area between the lungs)
• Retroperitoneal (back part of the abdomen)
• Sacrum or coccyx (lower part of the spine or tailbone)

How are extracranial germ cell tumors classified?

Extracranial germ cell tumors that form in reproductive organs (ovaries or testicles) are called gonadal germ cell tumors.

Sometimes, when the fetus is still forming, germ cells may travel to parts of the body where they normally should not and grow into a tumor. These tumors are called extragonadal germ cell tumors. 

About 50% of germ cell tumors in childhood occur outside the ovaries and testicles and usually grow along the midline (center) of the body.

What age groups are most affected by extracranial germ cell tumors?

Germ cell tumors can occur at any age but are mostly found in young children and teens between ages 15-19. Extracranial germ cell tumors account for about 3% of childhood cancers.

In children younger than 11, tumors usually occur at birth or in early childhood and are extragonadal in origin. They are mainly benign teratomas in the sacrum or coccyx.

In older children, adolescents, and young adults, extragonadal extracranial germ cell tumors are often seen in the mediastinum.

What are signs and symptoms of extracranial germ cell tumors?

Signs and symptoms depend on tumor size and location and may include:

How are extracranial germ cell tumors diagnosed?

Medical history, physical exam, and blood tests are performed to assess symptoms, general health, past illnesses, and risk factors.

• Family history is important in determining genetic risk.
• Blood tests are used to look for tumor markers, such as alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (β-HCG) substances.

Imaging tests may include:

A biopsy is used to confirm a diagnosis of a germ cell tumor.

How are childhood extracranial germ cell tumors treated?

Some extracranial germ cell tumors may be treated successfully with surgery alone. Chemotherapy may be used as well for more advanced diseases or to shrink the size of the tumor before surgery. 

If the tumor can be completely removed with surgery, prognosis is excellent. Research is underway to investigate targeted gene therapy and stem cell transplant as potential treatment options.