Yolk Sac Tumor

A yolk sac tumor — also called an endodermal sinus tumor — is a rare cancer that forms in cells that eventually become eggs or sperm. It’s a type of germ cell tumor. Yolk sac tumors can affect children and adults.

Yolk sac tumors usually start in the ovaries or testicles. In rare cases, these masses form in places other than your reproductive organs. They grow fast and spread quickly. They can be fatal without treatment.

But with early diagnosis, treatments can slow or prevent cancer spread. Early-stage yolk sac tumors are often curable.

Types

Types of yolk sac tumors include:

• Testicular yolk sac tumor: This form of testicular cancer is most common in children under 3 and adults in their 20s and 30s. Diagnosis often happens before the tumor has spread.
• Ovarian yolk sac tumor: This aggressive form of ovarian cancer is most common in people under 21 years of age. One-third of diagnoses involve children too young to have gotten their periods.
• Extragonadal yolk sac tumors: These form in places outside of your reproductive organs (your gonads), like your brain, chest, abdomen or tailbone.

Symptoms of yolk sac tumors

Symptoms of a yolk sac tumor depend on its location.

The main symptom of a testicular yolk sac tumor is a firm, painless lump in a testicle.

Symptoms of ovarian yolk sac tumors include:

• A mass or swelling in your abdomen
• Abdominal or back pain
• Changes in your pooping habits
• Irregular periods, including heavy period bleeding

Extragonadal yolk sac tumor symptoms vary by tumor location and may include:

• Brain: Headaches or vision issues
• Chest: Cough and shortness of breath
• Tailbone: A swollen area that looks like a bruise or infected bump

Yolk sac tumor causes

Medical researchers don’t know what causes yolk sac tumors. Like all cancers, they form when changes to the genes in cell DNA (mutations) cause cells to multiply too fast. Eventually, these cells form masses. Without treatment, cancer cells can spread.

Experts are still researching what starts this process in the first place.

How doctors diagnose yolk sac tumors

Your healthcare provider will ask about your symptoms. They’ll do a physical exam to check for unusual lumps or swelling in your abdomen or testicles.

They’ll recommend tests to help diagnose a yolk sac tumor, like:

• Blood tests: High levels of alpha-fetoprotein (AFP) suggest a yolk sac tumor.
• Imaging tests: CT scans and MRIs are the most common imaging tests providers use to detect these tumors.
• Surgical excision: A provider removes the entire mass (and sometimes, the entire affected organ). They send it to a lab to test for cancer cells. This is the only way to be sure a mass is a yolk sac tumor.

Staging yolk sac tumors

Your cancer care team will stage the yolk sac tumor. This helps determine how advanced the cancer is and the best treatment options.

Testicular yolk sac tumors range from stages 1 to 3:

• Stage 1: The cancer is only in your testicle.
• Stage 2: Cancer has spread to your lymph nodes.
• Stage 3: Cancer cells have spread to other organs.

Ovarian yolk sac tumors range from stages 1 to 4:

• Stage 1: The cancer hasn’t spread beyond one or both ovaries.
• Stage 2: Cancer cells have spread below your pelvis, but they’re not in your lymph nodes.
• Stage 3: The cancer has spread to your lymph nodes and the layer of tissue lining your abdomen (peritoneum) that’s outside your pelvis.
• Stage 4: Cancer has spread to tissues and organs other than your peritoneum.

How is it treated?

Treatment involves surgery to remove the entire yolk sac tumor. This typically means removing the affected testicle (orchiectomy) or ovary (oophorectomy). Your healthcare provider may also remove lymph nodes if the cancer has spread there.

Chemotherapy usually follows. This treatment uses drugs to kill any cancer cells that may remain. If a yolk sac tumor is so large that surgery may pose risks, you may need chemotherapy before surgery to shrink the tumor.

BEP chemotherapy for yolk sac tumors

BEP is a combination drug therapy for yolk sac tumors. It includes:

• Bleomycin sulfate
• Etoposide phosphate
• Cisplatin

When taken together, these drugs are powerful yolk sac tumor fighters. Depending on the cancer stage and your response to treatment, you may need one or more rounds of BEP.

When should I see my healthcare provider?

Regular checkups with your provider after cancer treatment (surveillance) are essential, especially within the first five years following treatment. Surveillance involves:

• Physical exams
• CT scans of your abdomen and pelvis
• Blood tests to check your AFP levels

The purpose of surveillance is to make sure the cancer isn’t back. If tests detect it, you can start treatment right away.

What can I expect if I have this condition?

Yolk sac tumors are life-threatening without treatment. This is why early diagnosis and treatment are so important. As with most cancers, the earlier you get treatment, the better your prognosis (outcome).

Still, your prognosis depends on different factors you’ll need to discuss with your provider, like the cancer stage and your body’s response to treatment. Alpha-fetoprotein (AFP) levels are also important. Lower AFP levels before chemotherapy typically suggest a better outcome.

Survival rates

The good news is that treatments like surgery and BEP improve the survival rate of people diagnosed with yolk sac tumors. For example, nearly all stage 1 testicular yolk sac tumors are curable with treatment.

A recent study tracking the survival of people treated for ovarian yolk cell tumors showed that about 9 out of 10 people with early-stage cancer were alive five years later. That number was around 3 out of 4 for people who had cancer spread beyond their ovaries.

Is there anything I can do to feel better?

Before starting yolk sac tumor treatment, ask your healthcare provider what side effects to expect and how to manage them.

You may also wish to ask your provider to connect you with resources that can assist with pain management. For example, palliative care can help you navigate treatment side effects, no matter your cancer stage or prognosis.