Malignant neoplasm of ovary

Your ovaries are two almond-sized organs located on either side of the uterus, or womb. They produce eggs and the hormones estrogen and progesterone. A malignant neoplasm—which is the medical term for a cancerous tumor—occurs when the cells in your ovaries begin to grow out of control and form a mass. Unlike healthy cells that grow and die in an orderly way, these abnormal cells continue to multiply and can eventually spread to other parts of the body.

While the exact reason these cells become cancerous is often unknown, it usually happens because of changes or mutations in a person's DNA, the internal "instruction manual" inside your cells. When these instructions are damaged, the cells stop functioning correctly and start growing into a tumor instead of staying healthy.