The ovaries are a pair of organs in the female reproductive system. They are located in the pelvis, one on each side of the uterus (the hollow, pear-shaped organ where a fetus grows). Each ovary is about the size and shape of an almond. The ovaries produce eggs and female hormones (chemicals that control the way certain cells or organs function).

An ovarian cyst may be found on the surface of an ovary or inside it. A cyst contains fluid. Sometimes it contains solid tissue, too. Most ovarian cysts are benign (not cancer) and go away with time. Sometimes, a doctor will find a cyst that does not go away or that gets larger. The doctor may order tests to make sure that the cyst is not cancer.

Ovarian cancer can invade, shed or spread to other organs:

• Invade. A malignant ovarian tumor can grow and invade organs next to the ovaries, such as the fallopian tubes and uterus.
• Shed. Cancer cells can shed (break off) from the main ovarian tumor. Shedding into the abdomen may lead to new tumors forming on the surface of nearby organs and tissues. The doctor may call these seeds or implants.
• Spread. Cancer cells can spread through the lymphatic system to lymph nodes in the pelvis, abdomen and chest. Cancer cells may also spread through the bloodstream to organs such as the liver and lungs.