Germ cell tumors are growths of cells that form from reproductive cells called germ cells. In the female reproductive system, germ cells turn into eggs. In the male reproductive system, they turn into sperm. Most germ cell tumors happen in the testicles or the ovaries.

Some germ cell tumors happen in other areas of the body, but they are very rare. These are called extragonadal germ cell tumors. Examples of where these tumors can form include the belly, brain and chest. It's not clear why germ cell tumors form in places other than the testicles and ovaries.

Some germ cell tumors may be cancer, but others are not cancer.

Treatment for germ cell tumors may include surgery, chemotherapy and radiation therapy.

Symptoms of germ cell tumors depend on where they happen. Symptoms often happen because a growing tumor puts pressure on nearby tissue or organs. For example, a germ cell tumor in an ovary may lead to pelvic pain, back pain, bloating or swelling in the belly. A germ cell tumor in a testicle may cause swelling or pain in the testicle or scrotum. A lump in the testicle is a common symptom of a testicular germ cell tumor.

It's not clear what causes germ cell tumors. Germ cell tumors form in the cells that turn into eggs in the ovaries and into sperm in the testicles. Germ cell tumors happen when germ cells develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA tells the cells to grow and multiply at a set rate. The DNA also tells the cells to die at a set time.

In tumor cells, the DNA changes give different instructions. The changes tell the tumor cells to grow and multiply quickly. Tumor cells can keep living when healthy cells would die. This causes too many cells. The tumor cells can form a mass that can grow and press on nearby tissue or organs.

Sometimes the DNA changes turn germ cells into cancer cells. Cancer cells can invade and destroy healthy body tissue. Cancer cells sometimes break away and spread to other parts of the body.

Factors that may raise the risk of germ cell tumors include:

• Young age. Germ cell tumors tend to happen at a young age. For example, germ cell tumors that form in the ovaries are more common before age 20. Germ cell tumors that form in the testicles are most common between the ages of 15 and 35.
• Undescended testicle. Having a testicle that doesn't move down into its proper place in the scrotum before birth may raise the risk of a germ cell tumor in that testicle. The medical term for this condition is cryptorchidism.

Healthcare professionals haven't found anything that can prevent germ cell tumors.

Tests and procedures used to diagnose germ cell tumors may include imaging tests, blood tests and surgery.

Imaging tests

Imaging tests make pictures of the body that can show the size and location of a tumor. Ultrasound is often used to make pictures of germ cell tumors in the ovaries and testicles. Ultrasound can give the healthcare team more information about lumps or masses that could be a germ cell tumor. It can help the care team see whether the lumps look like something that could be cancer or not cancer.

Other imaging tests might include computerized tomography scan, also called CT scan, and magnetic resonance imaging, also called MRI.

Blood tests

A blood test can find proteins made by cancer cells. This type of test is called a tumor marker test. Having these substances in the blood doesn't mean that someone has cancer. But if a level is higher than typical, that information can help the healthcare team better understand what's going on in the body.

Surgery

If a lump or mass could be cancer, surgery may be needed to remove it. Then the tissue is sent to a lab for testing. The tests can show whether it's cancer.

Treatments for germ cell tumors may include surgery, chemotherapy and radiation therapy.

Surgery

Surgery is often used to take out a germ cell tumor. The kind of surgery used to remove a germ cell tumor may depend on the tumor's location. If a tumor in a testicle might be cancer, surgery often includes removing the entire testicle.

Chemotherapy

Chemotherapy treats cancer with strong medicines. Many chemotherapy medicines exist. Most chemotherapy medicines are given through a vein. Some come in pill form.

Radiation therapy

Radiation therapy treats cancer with powerful energy beams. The energy can come from X-rays, protons or other sources. During radiation therapy, you lie on a table while a machine moves around you. The machine directs radiation to precise points on the body.

If you have any symptoms that worry you, start by making an appointment with a doctor or other healthcare professional. If your healthcare professional suspects that a germ cell tumor could be cancer, you may be referred to a doctor who specializes in cancer, called an oncologist.

Because appointments can be brief, it's a good idea to be prepared. The following information can help you get ready for an appointment.

What you can do

• Write down any symptoms you have, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Write down key personal information, including any major stresses or recent life changes.
• Make a list of all medicines, vitamins or supplements that you're taking.
• Consider taking along a family member or friend. Sometimes it can be hard to remember all the information you get during an appointment. Someone who goes with you may remember something that you missed or forgot.
• Write down questions to ask your healthcare professional.

Questions for your doctor

Below are some basic questions to ask your healthcare professional. If you think of other questions during your appointment, be sure to ask those questions too.

• What's likely causing my symptoms?
• Other than the most likely cause, what are other possible causes for my symptoms?
• What tests do I need?
• What's the best course of action?
• What are the alternatives to the approach you're suggesting?
• I have other health conditions. How can I best manage them together?
• Are there restrictions I need to follow?
• Should I see a specialist?
• Are there brochures or other printed material I can have? What websites do you recommend?

What to expect from your doctor

Questions your healthcare professional might ask include:

• When did your symptoms begin?
• Do you have symptoms all the time, or do they come and go?
• How bad are your symptoms?
• What, if anything, seems to make your symptoms better?
• What, if anything, seems to make your symptoms worse?

Being ready to answer these questions will help you make the most of your appointment time.