Health Library
Yolk Sac or Germ Cell Tumor

What is a Yolk Sac or Germ Cell Tumor?

A yolk sac tumor is a rare, malignant tumor of cells that line the yolk sac of the embryo. These cells normally become ovaries or testes. The cause of a yolk sac tumor is unknown. It is most often found in children before age 1 or 2, but can occur throughout life.

The term germ cell tumors encompasses many types of tumors, some are malignant and others are benign. These include yolk sac tumors, teratomas, embryonal carcinoma, dysgerminomas, semenoma, etc. These tumors can occur in the testes, ovaries, chest, brain and other parts of the body.

Last Updated 02/2025

Learn more about our editorial policy