Germinoma

What is a germinoma?

A germinoma is a type of germ cell tumor that forms in your brain. They’re also called “intracranial germinomas.” Most form in either the pineal region of your brain (where your pineal gland is) or the suprasellar region (where your pituitary gland is).

Germ cell tumors (GCTs) form from reproductive cells that eventually become eggs or sperm. Related, most GCTs start in the organs that house these cells — your ovaries or testicles. But germinomas are different. With a germinoma, the cells travel to your brain or spine. Once there, they grow and form masses. Although they can be benign (noncancerous), most germinomas are malignant (cancerous) tumors.

Still, germinomas have an excellent outlook (prognosis). They grow slowly and are usually curable with treatment.

How common are germinomas?

Brain germ cell tumors are rare. But germinomas are the most common type of these rare tumors. They’re most commonly diagnosed in children, teens and young adults. People assigned male at birth are more likely to develop them.

What are the symptoms of a germinoma?

Germinomas can cause cerebrospinal fluid (CSF) to build up in your brain (hydrocephalus). The pressure from the tumor or the fluid buildup can lead to symptoms like:

• Headaches.
• Nausea and vomiting.
• Problems with muscle coordination (ataxia).
• Vision issues (including blurred vision, double vision and an inability to look upward).
• Mood changes.
• Trouble concentrating.
• Fatigue.

Depending on where the tumor is located, germinomas may also cause hormone-related symptoms, like:

• Excessive thirst or having to pee a lot (signs of diabetes insipidus).
• Early or delayed puberty.
• Stunted growth in children.
• Excessive sleepiness or sluggishness.

What causes a germinoma?

With a germinoma, the reproductive cells that normally travel to your ovaries or testicles during fetal development take a detour to your central nervous system. Instead of becoming egg or sperm cells, they form an abnormal mass in one or more parts of your brain. Without treatment, the cells can spread to other parts of your body.

Medical experts don’t know what causes this to happen in the first place.

How is a germinoma diagnosed?

Tests to diagnose a germinoma include:

• Imaging tests. A brain MRI can show tumors in your brain or spine.
• Tests to check for tumor markers. Your healthcare provider may check the levels of alpha-fetoprotein (AFP) or human chorionic gonadotropin (hCG) in your blood and cerebrospinal fluid. These numbers can help distinguish germinomas from other types of germ cell tumors.
• Biopsy. A provider may remove a sample of the germinoma to test it in a lab for cancer cells. Usually, you only need a biopsy if the other tests don’t provide enough information for a diagnosis.

In children, germinomas can take some time to diagnose because some of the signs — like trouble concentrating or sluggishness — are more commonly related to mental health conditions. No matter the cause, the sooner your child is diagnosed, the sooner they can get the treatment they need.

Staging

Your healthcare provider will stage the germinoma to determine the extent of the cancer spread. They’ll classify it as either localized (M0) or disseminated/metastatic (M+). Localized means that the germinoma hasn’t spread. Disseminated/metastatic means that it has.

These classifications help providers plan treatment.

How are germinomas treated?

Most germinomas are curable with radiation therapy. This treatment directs X-rays toward the germinoma to destroy the tumor. But radiation therapy can cause unpleasant short-term and long-term side effects. It may also increase the risk of developing a different cancer in the future.

For this reason, radiation oncologists plan treatment carefully. The goal is to give the maximum dosage needed to get rid of tumors while reducing the risk of side effects. In some cases, providers recommend chemotherapy treatment to shrink tumors before radiation. That way, they can treat the germinoma using a lower radiation dose.

What can I expect if I have a germinoma?

The outlook for germinomas is excellent. The 10-year survival rate for people with germinomas treated with radiation therapy is more than 90%. Tumors rarely come back. When they do, more rounds of radiation therapy often get rid of them for good.

Still, everyone’s journey is different. Ask your healthcare provider how your diagnosis and treatment will impact your outlook.

How do I take care of myself?

With germinomas, one of the best things you can do is to work closely with your healthcare provider to manage side effects. Radiation therapy and chemotherapy are effective germinoma treatments. But this doesn’t mean they won’t take a physical or emotional toll.

No one can predict your unique response to treatment. Still, your provider can guide you on side effects people commonly experience. Understanding the possibilities can help you feel prepared.

If you’re supporting a child through cancer treatment, take steps to communicate what’s going on at an age-appropriate level. Be present for your child. Rally your support network, too. Take advantage of the resources you need to be a strong caregiver for your child.

When should I see my healthcare provider?

See your healthcare provider if you’re experiencing frequent headaches, having vision issues or noticing other symptoms that may be signs of a brain tumor. Schedule an appointment if you’re noticing these signs in your child.

What questions should I ask my healthcare provider?

Questions to ask include:

• What stage is the germinoma, and where is it located?
• What treatments do you recommend?
• How can I manage short-term treatment side effects?
• What long-term side effects should I be on the lookout for?
• How often will I need follow-up visits?