Yolk Sac Tumor

What is a yolk sac tumor?

A yolk sac tumor — also called an endodermal sinus tumor — is a cancer that forms in cells that eventually become eggs or sperm. A type of germ cell tumor, yolk sac tumors usually start in either your ovaries or testicles. But in rare cases, these masses form in places other than your reproductive organs.

Although they’re rare overall, yolk sac tumors are the most common type of cancerous germ cell tumor diagnosed in children. They grow fast and spread quickly. They’re potentially fatal without treatment. But with early diagnosis, treatments can slow or prevent cancer spread. Early-stage yolk sac tumors are often curable.

Types of yolk sac tumors

Types of yolk sac tumors include:

• Testicular yolk sac tumors. A form of testicular cancer, these tumors are most common in children under 3 and people in their 20s and 30s. They’re usually diagnosed before they spread, while they’re curable.
• Ovarian yolk sac tumors. This aggressive form of ovarian cancer is most common in people 20 years old or younger. One-third of diagnoses involve children too young to have gotten their periods.

Like other types of germ cell tumors, yolk sac tumors sometimes form in places outside of your reproductive organs, in places like your brain, chest, abdomen or tailbone. These are called extragonadal germ cell tumors.

What are the symptoms of a yolk sac tumor?

Signs and symptoms of a yolk sac tumor depend on where it’s located and may include:

• A firm, painless lump in a testicle
• Swelling in your abdomen or a mass (ovaries)
• Abdominal pain or back pain (ovaries)
• Changes in your bowel habits (ovaries)
• Irregular periods, including heavy period bleeding (ovaries)
• Headaches or vision issues (brain)
• Cough and shortness of breath (chest)
• A swollen area resembling a bruise or infected bump (in your tailbone)

What causes yolk sac tumors?

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

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

How are yolk sac tumors diagnosed?

Diagnosis involves a physical examination to check for signs of a yolk sac tumor, like unusual lumps or swelling in your abdomen or testicles. Your healthcare provider will also ask about your symptoms.

Tests you may need include:

• Blood tests. Your provider will check your blood for high levels of alpha-fetoprotein (AFP). Nearly all yolk sac tumors secrete this protein.
• Imaging tests. Computed tomography (CT) scans and magnetic resonance imaging (MRI) are the most common imaging tests providers use to detect these tumors.
• Surgical excision. Your provider will remove the entire mass (and sometimes, the entire organ containing the mass) and test it in a lab for cancer cells. This is the only way to be sure a mass is a yolk sac tumor.

Staging yolk sac tumors

Healthcare providers stage yolk sac tumors to determine how advanced the cancer is and find the best treatment options. Using information like tumor size and the extent of cancer spread, they assign a number or “stage.” Lower numbers mean that cancer is in the early stages. Higher numbers mean more advanced cancer.

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 are yolk sac tumors treated?

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

Chemotherapy treatment (chemo) usually follows. This treatment uses chemotherapy 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. Depending on the cancer stage and your response to treatment, you may need one or more rounds of BEP. BEP includes the chemotherapy drugs:

• Bleomycin sulfate
• Etoposide phosphate
• Cisplatin (Platinol^®)

When taken together, these drugs are powerful yolk sac tumor fighters.

What is the prognosis for yolk sac tumors?

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 this treatment. A recent study tracking the survival of people treated for ovarian yolk cell tumors showed that 91.5% with early-stage cancer were alive five years later. That number was 74.8% for people who had cancer spread beyond their ovaries.

How do I take care of myself?

Navigating a yolk sac tumor diagnosis can be hard. In addition to the stress of having cancer, you also have to manage the challenges of managing treatment side effects. For example, yolk sac treatment often requires several rounds of chemo, which can cause unpleasant side effects.

Before treatment, ask your healthcare provider what side effects to expect and how to manage them. Ask them to connect you with available resources that can help with pain management, like palliative care. This care option can help you navigate treatment side effects, no matter your cancer stage or prognosis.

When should I see my healthcare provider?

Surveillance (regular check-ups with your provider after cancer treatment) is essential. This is especially the case within the first five years following treatment. Surveillance involves:

• Physical scans
• 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 your healthcare provider detects it, they can treat it right away.

What questions should I ask my healthcare provider?

Questions to ask include:

• What is the cancer stage?
• Which treatments will I need?
• What side effects should I expect during treatment?
• How will we know if the treatment worked?