Ovarian cancer is one of leading cause of death in female population all over the world – it is the fifth most common cancer in women. The majority of ovarian cancer types are classified as epithelial because the multiplication of cancerous cells arises from the epithelial surface of the ovary.
Ovarian cancer could appear at any age but the number of cases is highest in the 60-70 age range. Elderly women are more likely than younger women to be in an advanced stage of disease at initial diagnosis.
Main ovarian cancer types
Ovarian cancer types can be different – classified according to the cell from which they start.
Medical experts identify about 35 types and sub-types of ovarian malignancies. Each type of ovarian cancer has specific histological description, appearance, symptoms and survival rates.
Main three categories of ovarian cancer include the following:
Ovarian cancer types
- Epithelial ovarian tumors (arise from cells that line or cover the ovaries);
- Germ cell ovarian tumors (arise from cells that are “programmed” to form eggs inside of ovaries);
- Sex cord-stromal cell ovarian tumors (arise in the connective cells that hold ovaries together and produce female hormones).
Epithelial ovarian tumors
Epithelial ovarian cancer is the most common type and diagnosed in about 90% cases of all ovarian cancers. Usually epithelial tumors arise in the surface epithelium of the ovaries – it starts in the cells that cover the lining of the Fallopian tube or the ovary. Epithelial ovarian tumors have several sub-types. Oncology experts highlight that each sub-type of ovarian tumors should be treated as different types of cancer rather than as one disease.
Serous ovarian tumors (40% of epithelial tumors) are malignant in 50% cases. More often these types are diagnosed at 40-60 age groups. Women with this type of ovarian cancer often have an inherited abnormality in their BRCA1/2 genes.
Endometrioid ovarian tumors (20% of epithelial tumors) are associated with endometrial carcinoma (arise from uterus lining). Sometimes these tumors are linked with endometriosis (only in 5% cases). About 80% of endometrioid tumors are malignant. More common appear at 50-70.
Mucinous ovarian tumors (1% of epithelial tumors) are benign in 80% cases. Mucinous tumors appear most often in women between 30 to 50 years of age.
Clear cell carcinoma (6% of epithelial tumors) is usually malignant. This type of ovarian cancer is often associated with endometriosis. Most women with clear cell carcinoma are between 40 and 80 years of age.
Germ cell ovarian tumors
Ovarian cancer risks
Germ cell ovarian tumors (5-10% of ovarian cancer cases) start their grow from the tissue which supposed to form eggs within the ovaries – derived from primitive germ cells of embryonic gonad. This type of ovarian tumors is diagnosed in about 3% cases of all ovarian cancers. Germ cell ovarian tumors tend to occur in young women who are in their early 20s. In many cases these tumors are hormone-sensitive and modern treatments can be pretty effective with high survival rates.
Medical experts recognize different types of germ cell tumors – Dysgerminoma, Endodermal sinus tumours, Teratoma, Embryonal carcinoma, Choriocarcinoma and Sarcomas.
Sex cord-stromal ovarian tumors
Sex cord-stromal ovarian tumors (5% of all ovarian cancers) derive from connective tissue cells. They are formed from cells of the sex cord or mesenchyme (early connective tissue) within the embryonic gonad – they may contain gonad-related cells as well as fibroblasts (immature connective tissue-forming cells).
Cells in sex cord-stromal ovarian tumors may produce female hormones. These tumors are associated with hormonal effects such as virilization (increased male hormones), precocious puberty (early sexual maturity), amenorrhea (absence of menstrual periods) and menopause (biological hormone reductions).
The most common tumors in this sub-type are granulosa stromal cell tumors (common in postmenopausal women) and Sertoli-Leydig cell tumors (common in young women with average age 25).
Other tumors from this group are fibroma, fibrosarcoma, lipid cell tumors and gynandroblastomas.
