Ovarian Yolk Sac Tumor

**Semantic type:** Neoplastic Process

**Definition:** A usually rapidly growing malignant germ cell tumor arising from the ovary. It usually occurs in children and adolescents. Signs and symptoms include abdominal pain and a large abdominal or pelvic mass. The serum alpha-fetoprotein is almost always elevated preoperatively. Morphologically, there is marked heterogeneity due to numerous patterns of differentiation coexisting in the same tumor. The most common pattern is reticular.

**Synonyms:** - Endodermal Sinus Neoplasm of Ovary - Endodermal Sinus Neoplasm of the Ovary - Endodermal Sinus Tumor of Ovary - Endodermal Sinus Tumor of the Ovary - Germ Cell Endodermal Sinus Neoplasm of Ovary - Germ Cell Endodermal Sinus Neoplasm of the Ovary - Germ Cell Endodermal Sinus Tumor of Ovary - Germ Cell Endodermal Sinus Tumor of the Ovary - Ovarian Endodermal Sinus Neoplasm - Ovarian Endodermal Sinus Tumor - Ovarian Germ Cell Endodermal Sinus Neoplasm - Ovarian Germ Cell Endodermal Sinus Tumor - Ovarian Yolk Sac Neoplasm - Yolk Sac Neoplasm of Ovary - Yolk Sac Neoplasm of the Ovary - Yolk Sac Tumor of Ovary - Yolk Sac Tumor of the Ovary