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Extragonadal Germ Cell Tumour

Definition of extragonadal germ cell tumour: 

A rare cancer that develops in germ cells that are found in areas of the body other than the ovary or testicle (such as the brain, chest, abdomen, or tailbone). Germ cells are reproductive cells that develop into sperm in males and eggs in females. 

Extragonadal germ cell tumours form from developing sperm or egg cells that travel from the gonads to other parts of the body.

"Extragonadal" means outside of the gonads (sex organs). When cells that are meant to form sperm in the testicles or eggs in the ovaries travel to other parts of the body, they may grow into extragonadal germ cell tumours. These tumours may begin to grow anywhere in the body but usually begin in organs such as the pineal gland in the brain, in the mediastinum, or in the abdomen.

Extragonadal germ cell tumours can be benign (noncancer) or malignant (cancer). Benign extragonadal germ cell tumours are called benign teratomas. These are more common than malignant extragonadal germ cell tumours and often are very large.

Malignant extragonadal germ cell tumours are divided into two types, nonseminoma and seminoma. Nonseminomas tend to grow and spread more quickly than seminomas. They usually are large and cause symptoms. If untreated, malignant extragonadal germ cell tumours may spread to the lungs, lymph nodes, bones, liver, or other parts of the body.

For information about germ cell tumours in the ovaries and testicles, see the following summaries in the A-Z List of Cancers:

Age and gender can affect the risk of extragonadal germ cell tumours.

Anything that increases your chance 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. Talk with your doctor if you think you may be at risk. Risk factors for malignant extragonadal germ cell tumours include the following:

  • Being male.
  • Being age 20 or older.
  • Having Klinefelter syndrome.

Possible signs of extragonadal germ cell tumours include chest pain and breathing problems.

Malignant extragonadal germ cell tumours may cause symptoms as they grow into nearby areas. Other conditions may cause the same symptoms. Check with your doctor if you have any of the following problems:

  • Chest pain.
  • Breathing problems.
  • Cough.
  • Fever.
  • Headache.
  • Change in bowel habits.
  • Feeling very tired.
  • Trouble walking.
  • Trouble in seeing or moving the eyes.

Imaging and blood tests are used to detect (find) and diagnose extragonadal germ cell tumours.

The following tests and procedures may be used:

  • Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. The testicles may be checked for lumps, swelling, or pain. A history of the patient's health habits and past illnesses and treatments will also be taken.
  • Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
  • Serum tumour marker test: A procedure in which a sample of blood is examined to measure the amounts of certain substances released into the blood by organs, tissues, or tumour cells in the body. Certain substances are linked to specific types of cancer when found in increased levels in the blood. These are called tumour markers. The following three tumour markers are used to detect extragonadal germ cell tumour:
    • Alpha-fetoprotein (AFP).
    • Beta-human chorionic gonadotropin (β-hCG).
    • Lactate dehydrogenase (LDH).

Blood levels of the tumour markers help determine if the tumour is a seminoma or nonseminoma.

  • CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
    Sometimes a CT scan and a PET scan are done at the same time. A PET scan is a procedure to find malignant tumour cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumour cells show up brighter in the picture because they are more active and take up more glucose than normal cells do. When a PET scan and CT scan are done at the same time, it is called a PET-CT.
  • Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. The type of biopsy used depends on where the extragonadal germ cell tumour is found.
    • Excisional biopsy: The removal of an entire lump of tissue.
    • Incisional biopsy: The removal of part of a lump or sample of tissue.
    • Core biopsy: The removal of tissue using a wide needle.
    • Fine-needle aspiration (FNA) biopsy: The removal of tissue or fluid using a thin needle.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options depend on the following:

  • Whether the tumour is nonseminoma or seminoma.
  • The size of the tumour and where it is in the body.
  • The blood levels of AFP, β-hCG, and LDH.
  • Whether the tumour has spread to other parts of the body.
  • The way the tumour responds to initial treatment.
  • Whether the tumour has just been diagnosed or has recurred (come back).

For more information on Extragonadal Germ Cell tumour click here

This link is to the National Cancer Institute (NCI) cancer website in the United States. There may be references to drugs and clinical trials that are not available here in Australia.