Yolk Sac Tumor


Germ Cell Tumor


Yolk sac tumor (medical condition): A form of malignant germ cell tumor that occurs mainly in young children. They can occur in the testis, ovaries, uterus, abdomen , thorax, tailbone region (sacrococcygeal area), vagina, liver, retroperitoneum and pineal ventricle of the brain. 

Yolk sac tumors are also known as germ cell tumors, teratomas, or embryonal carcinoma.


Symptoms will vary depending on the exact location of the tumor

  • Asymptomatic in early stages (in the ovary it is not as visible and the tumor may grow very large before being noticed)
  • Increased serum alpha-fetoprotein level
  • Testicular swelling
  • Swelling on the buttocks (sacrococcygeal area)
  • Hydrocephalus


The cause of a yolk sac tumor is unknown. It is most often found in children before the ages of 1 to 2.


These cancer cells secrete specific hormones, two of which are alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG).

A blood test which shows an increase in either of these can help with the diagnosis. Other studies may include an ultrasound, CT scan, or MRI of the pelvis and a biopsy of the suspicious mass. 

Germ cell tumors can be diagnosed in utero. Sacrococcygeal teratomas are the most common germ cell tumor of childhood and the most frequently recognized neoplasm of the fetus.


Prognosis for germ cell tumors varies greatly depending on multiple factors, including child's age, tumor location, and staging.


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