Ovarian Germ Cell Tumors

Ovarian germ cell tumors are growths that occur most often in people 30 and under. The tumors are usually benign (noncancerous) but can be cancerous. Most ovarian germ cell tumors are treatable with surgery. For malignant tumors, your prognosis depends on the tumor type and whether the cancer’s spread.


What are ovarian germ cell tumors?

Ovarian germ cell tumors develop from reproductive cells (germ cells) inside your ovaries. Ovaries are two small pelvic organs that play an important role in the female reproductive system. They produce eggs during your reproductive years. The germ cells inside your ovaries eventually mature (“germ”-inate) into eggs. With ovarian germ cell tumors, some of these cells clump together to form an abnormal mass instead.

Ovarian germ cell tumors usually form in just one ovary, but sometimes they appear in both.

Most ovarian germ cell tumors are benign (noncancerous). Rarely, they can be malignant (cancerous). These tumors can spread and damage healthy tissue. Malignant germ cell tumors are a rare form of ovarian cancer.

What are the types of ovarian germ cell tumors?

The most common types of ovarian germ cell tumors are:

  • Mature teratoma (dermoid cyst): These benign tumors are the most common type of ovarian germ cell tumor. Most people diagnosed are in their teens, 20s or 30s.
  • Dysgerminoma: This is the most common type of malignant ovarian germ cell tumor. But most of these tumors (70% of diagnoses) aren’t considered aggressive (fast-spreading) and respond well to treatment. Most people diagnosed are in their 20s or 30s.
  • Immature teratoma: This is a fast-growing malignant tumor that can spread from your ovary to other parts of your body (metastasis). It’s most common in people 20 years old and younger.
  • Yolk sac tumors (endodermal sinus tumors): These malignant tumors grow quickly and spread fast. They’re most common in people 20 years old and younger. Up to 40% of diagnoses involve children who are too young to have started their periods.
  • Mixed germ cell tumors: These malignant tumors contain a mix of other tumor types, usually dysgerminoma and yolk sac tumors.

Rarer ovarian germ cell tumors include:

How common are ovarian germ cell tumors?

Ovarian germ cell tumors are most common in people assigned female at birth (AFAB) in their reproductive years or younger. They account for up to 70% of ovarian growths in people between 10 to 30 years old. They’re less common in people over 40.

Approximately 95% of ovarian germ cell tumors are benign (mature teratomas). Only 2% to 3% of ovarian cancers are germ cell tumors.


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Symptoms and Causes

What are the symptoms of ovarian germ cell tumors?

It may be difficult to spot signs of ovarian germ cell tumors early on. Benign tumors may not cause symptoms unless they’re large. Symptoms of malignant tumors may not appear until the cancer has advanced.

Symptoms to look out for include:

These tumors can release hormones that can cause changes in your body, including symptoms of:

  • Early pregnancy, like fatigue, nausea or breast tenderness.
  • Early puberty, although this is rare.

What causes ovarian germ cell tumors?

Ovarian germ cell tumors form when sex cells (germ cells) undergo changes (mutations) and form a mass. Experts continue to research why this happens, including who’s most likely to develop them.

Although anyone with ovaries can develop these tumors, ovarian germ cell tumors are much more common among people in their reproductive years and younger.


What are the complications of ovarian germ cell tumors?

Treatment is important because even if a tumor is benign, it can potentially burst open (rupture) or twist (ovarian torsion). This is more likely to happen if a tumor is large.

Removing the tumor can keep this from happening.

Diagnosis and Tests

How do healthcare providers diagnose ovarian germ cell tumors?

After asking about your symptoms, your provider will perform several tests, including a pelvic exam to check for growths and other abnormalities in your abdomen, pelvis and vagina. You may also need imaging and blood tests.

Your provider will need to remove the tumor or the entire affected ovary to make a definitive diagnosis. A pathologist will test the cells in a lab to determine the type of tumor and whether it’s benign or malignant.

What are the stages of malignant ovarian germ cell tumors?

If a tumor is malignant, providers classify the cancer using a process called staging as part of your diagnosis. They use imaging procedures, like a CT scan or PET scan (positron emission tomography scan), to measure the tumor size and determine its location. This information helps your provider determine what treatments you’ll need and the likely outcomes of treatment.

Usually, the lower the stage, the more treatable the cancer is.

Stages for malignant ovarian germ cell tumors are:

  • Stage 1: The cancer is just in your ovaries.
  • Stage 2: The cancer has spread to other tissues in your pelvis, including your fallopian tubes or uterus.
  • Stage 3: The cancer has spread to your lymph nodes or the tissue lining your pelvic organs or abdominal cavity (peritoneum), but it hasn’t spread beyond your abdomen.
  • Stage 4 (metastatic cancer): The cancer has grown into your liver or spleen or spread to tissues and organs outside your abdomen, like your lungs.


Management and Treatment

How are ovarian germ cell tumors treated?

Most germ cell tumors are treatable. Your treatment plan will depend on the tumor’s size and whether it’s benign or malignant.

Regardless, your provider will take care to conserve as much of your ovary as possible to preserve your fertility if you’re in your reproductive years.

Benign (noncancerous) ovarian germ cell tumors

Healthcare providers remove benign tumors surgically. Sometimes, they need to remove the entire ovary (oophorectomy) or part of the ovary (ovarian cystectomy) to get rid of the growth. They may recommend open surgery (laparotomy) or a less invasive type of surgery that involves smaller incisions (laparoscopy).

Benign tumors rarely grow back after providers remove them.

Malignant (cancerous) ovarian germ cell tumors

Treatment depends on the type of tumor and the cancer stage. Common treatments include:

  • Surgery: Your provider may recommend an oophorectomy to remove one or both of your ovaries or fallopian tubes. If cancer has spread beyond your ovaries and fallopian tubes, you may need a total hysterectomy to remove your uterus and cervix.
  • Chemotherapy: During chemotherapy, your provider delivers medicine into your veins, usually through an infusion. Chemotherapy drugs kill cancerous cells and stop them from multiplying. You may receive chemo treatments over several weeks or months.


Can I prevent ovarian germ cell tumors?

You can’t prevent germ cell tumors. But you can get regular checkups so your provider can monitor your health and assess your cancer risk.

Outlook / Prognosis

What is the outlook for people with ovarian germ cell tumors?

The outlook for benign ovarian germ cell tumors is excellent. Benign tumors usually don’t grow back after providers remove them.

The outlook for malignant germ cell tumors varies depending on the tumor type and cancer stage. Cancer specialists determine outlook by calculating how many people with a specific cancer are alive five years after their diagnosis, or the five-year survival rate.

If cancer hasn’t spread beyond your ovaries, there is a 94% to 98% survival rate. Cancers that have spread farther away from the original tumor site have a 73% five-year survival rate. Your provider will monitor you closely during this period to ensure you receive treatment if the cancer returns (recurs).

Is ovarian germ cell cancer curable?

It can be, depending on the type of tumor and the stage. For example, the cure rate for early-stage dysgerminoma treated with chemotherapy is nearly 100%. More aggressive types, like yolk sac tumors, aren’t curable, but treatment can slow tumor growth and cancer spread.

Your provider can explain the prognosis for ovarian germ cell cancer (including the possibility of a cure) based on your diagnosis.

Living With

When should I see my healthcare provider about ovarian germ cell tumors?

See a provider immediately if you or your child experiences symptoms of an ovarian germ cell tumor. Some germ cell tumors grow quickly. Finding them early and getting treatment as soon as possible can improve the outlook significantly.

What questions should I ask my healthcare provider?

If you learn you have an ovarian germ cell tumor, questions to ask include:

  • Is the tumor benign or malignant?
  • What tests will I need to determine what treatments I’ll need?
  • What treatments would you recommend?
  • What can I expect after treatment?
  • Will my diagnosis or treatment affect my ability to have a baby?

A note from Cleveland Clinic

See a provider immediately if you or your child experiences symptoms of an ovarian germ cell tumor. In most cases, they’re benign (noncancerous). Surgery can prevent complications like a large tumor bursting or twisting. In the rare instance that a tumor is malignant (cancerous), getting diagnosed and treated early can significantly improve your outlook. Even if you’re not experiencing symptoms, talk to your provider about scheduling regular checkups to monitor your reproductive health and organs.

Medically Reviewed

Last reviewed on 01/23/2024.

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