are cancer. Malignant cancer will spread beyond the ovary, invading and damaging other organs of the body. The spread of cancer beyond its tissue of origin is called metastasis.
Introduction
Germ cell neoplasms are thought to be derived from primitive germ cells of the embryonic gonad. They constitute the second largest group of ovarian neoplasms (~20%).These tumors can occur in women at any age, but peak incidence is seen during the early 20's. In children and adolescents, >60% of ovarian neoplasms are of germ cell origin, of which ~1/3 are malignant. In adults, the vast majority of germ cell tumors are benign (nearly all mature cystic teratomas). Dysgerminoma is the most common germ cell tumor, accounting for 50% of all germ cell tumor cases. About 20% of cases are diagnosed during pregnancy, and 80% occur in women under 30. Yolk sac tumors (also known as Endodermal sinus tumors) are the second most common germ cell tumor, accounting for 20% of all cases, and are common in girls and young adults (average age: 19). Less common germ cell tumors are embryonal carcinoma, immature teratoma, choriocarcinoma, polyembryomas, and mixed germ cell tumors.
Classification of germ cell neoplasms
Teratoma
- Mature cystic teratoma
- most common ovarian teratoma and most common ovarian germ cell tumor
- typically occurs during reproductive years
- cystic tumor with firm capsule, filled with sebaceous material and hair (occasionally teeth can be found)
- thickened area from which hair and teeth arise is called "Rokitansky's protuberance"
- composed of mature elements derived from all three germ layers (ectodermal elements such as skin, hair, sebaceous glands, and mature neural tissue predominate; cartilage, bone, respiratory and intestinal epithelium are common)
- complications include torsion, rupture, infection, hemolytic anemia
- benign neoplasm
- Monodermal teratoma
- a teratoma composed predominantly of one tissue element
- most common type is "struma ovarii", which is mature thyroid tissue
- Immature teratoma
- occurs in children and young adults
- usually a unilateral, solid tumor
- similar to mature teratoma but contains immature or embryonal tissues
- immature elements are almost always immature neuroepithelium
- graded on the basis of the quantity of immature tissue
- malignant neoplasm
Dysgerminoma
- 3-5% of ovarian malignant tumors
- most common malignant ovarian germ cell tumor
- typically occurs in 2nd and 3rd decades
- typically a unilateral, solid, firm to fleshy tumor
- composed of malignant germ cells, similar to primordial germ cells, admixed with nonneoplastic chronic inflammatory cells and occasionally granulomatous inflammation
- malignant neoplasm that is highly sensitive to radiation and/or chemo therapy
Yolk Sac Tumor
- second most common malignant ovarian germ cell tumor
- occurs in childhood, adolescence, and adult life (most <30 years)
- can be pure or a component of a mixed germ cell tumor
- almost always a unilateral solid or solid and cystic tumor
- displays a wide range of histologic patterns (microcystic, endodermal sinus, solid, alveolar-glandular, papillary, myxomatous, macrocystic, hepatoid, primitive endodermal, polyvesicular vitelline)
- classic pattern shows perivascular formations (Schiller-Duval bodies) and eosinophilic globules that contain AFP
- associated with elevated serum AFP levels
- highly malignant neoplasm that is radioresistant but responds to combination chemotherapy
Embryonal Carcinoma
- uncommon ovarian germ cell neoplasm
- occurs in children and young adults
- usually occurs in combination with yolk sac tumor
- typically a unilateral, solid tumor with hemorrhage and necrosis
- composed of undifferentiated, pleomorphic, large cells
- highly malignant neoplasm that is radioresistant but responds to combination chemotherapy
Choriocarcinoma
- very rare as a pure ovarian neoplasm or as a component of a mixed germ cell tumor
- occurs in children and young adults
- associated with elevated serum hCG levels
- typically a unilateral, solid, hemorrhagic tumor
- composed of malignant cytotrophoblast and syncytiotrophoblast
- nongestational choriocarcinoma is a highly malignant neoplasm that responds to combination chemotherapy
Treatment of germ cell neoplasms