Ovarian cancer begins in the ovaries. Ovaries are reproductive glands found only in females (women). The ovaries produce eggs (ova) for reproduction. The eggs travel through the fallopian tubes into the uterus where the fertilized egg implants and develops into a fetus. The ovaries are also the main source of the female hormones estrogen and progesterone. One ovary is on each side of the uterus in the pelvis.
The ovaries are made up of 3 main kinds of cells. Each type of cell can develop into a different type of tumor:
Epithelial tumors start from the cells that cover the outer surface of the ovary. Most ovarian tumors are epithelial cell tumors.
Germ cell tumors start from the cells that produce the eggs (ova).
Stromal tumors start from structural tissue cells that hold the ovary together and produce the female hormones estrogen and progesterone.
Most of these tumors are benign (non-cancerous) and never spread beyond the ovary. Benign tumors can be treated by removing either the ovary or the part of the ovary that contains the tumor.