• Surface epithelial cells
• Germ cells
• And the sex cord-stromal cells

Any cancer cells that invade the ovaries and begin to grow within the ovaries are not considered or referred to as Ovarian Cancer.

Many types of tumors can start to form within the ovary organs of a woman. A few of these types are considered to be benign or noncancerous. In these cases the patient can be cured by surgically removing one ovary or the part of the ovary containing the tumor. Other types of Ovarian Cancer are malignant or cancerous. Treatment options and outcomes for patients that have contracted these types of Ovarian Cancer depend on the exact classification of the Ovarian Cancer and how far it has spread before it is diagnosed. Ovarian Tumors are named according to the category of cells from which the tumor originated and whether the tumor is classified as benign or cancerous.

The three main classifications of Ovarian Tumors are:

• Epithelial Tumors
• Germ Cell Tumors
• Stromal Tumors