Yolk Sac Tumor

A yolk sac tumor is a rare and aggressive type of germ cell tumor that most often affects the ovaries or testes. It is also known as an endodermal sinus tumor. Yolk sac tumors are more common in children and young adults, but they can occur at any age.

These tumors grow quickly and can spread if not treated promptly. Despite their aggressive nature, yolk sac tumors are highly responsive to modern chemotherapy. With early diagnosis and appropriate treatment, the outlook for many patients is favorable.

Symptoms

Symptoms of a yolk sac tumor vary depending on the location of the tumor and how advanced it is. Common symptoms may include:

• A painless lump or swelling in the testicle

• Abdominal or pelvic pain

• Abdominal swelling or a feeling of fullness

• Nausea or vomiting

• Unexplained weight loss

• Fatigue

In children, symptoms may be nonspecific and related to abdominal discomfort or swelling.

Causes

The exact cause of yolk sac tumors is not fully understood. They develop from germ cells, which are the cells responsible for forming eggs or sperm. During early development, these cells may undergo abnormal changes that lead to tumor formation.

Yolk sac tumors produce a protein called alpha-fetoprotein, or AFP, which is often used as a marker to help diagnose the condition and monitor treatment response.

Risk factors

Factors that may increase the risk of developing a yolk sac tumor include:

• Young age, particularly in infancy and early childhood

• Male sex, for testicular yolk sac tumors

• Female sex, for ovarian yolk sac tumors

• Certain genetic or developmental abnormalities affecting germ cells

In many cases, no clear risk factor can be identified.

Complications

If not treated promptly, yolk sac tumors can lead to serious complications, including:

• Spread of cancer to other organs, such as the lungs or liver

• Organ damage due to tumor growth

• Fertility problems, depending on tumor location and treatment

• Side effects related to chemotherapy or surgery

Regular follow-up is important to detect recurrence or treatment-related complications.

Prevention

There is no known way to prevent yolk sac tumors because the exact cause is unclear and they are often related to early cell development. However, early detection improves outcomes. Helpful steps include:

• Seeking medical evaluation for unexplained lumps, swelling, or persistent pain

• Regular health checkups, especially for children with unexplained abdominal symptoms

• Following recommended follow-up care after treatment to detect recurrence early

Prompt diagnosis and advances in treatment have greatly improved survival rates for yolk sac tumors.