Cancer in any part of the body is caused by tumorous cells spreading and multiplying throughout the body. These cells can be divided into different types and forms which determine the type of cancer one has and its treatment. Ovarian cancer is basically caused by three different kinds of tumors, giving rise to three different types of ovarian cancer. These are known as epithelial tumors, Germ Cell tumors and Stromal tumors. All three of them affect different parts of the ovary and vary in their rates of occurrence. All three of these however, can have effects such as producing masculine features and hirsutism in the patient because of production of male sex hormones.

Epithelial Tumors are formed from the surrounding tissue of the ovary. These are the most common kind of tumors that is seen among women, affecting close to 80% of all ovarian cancer patients. It is what is usually known as ovarian cancer as such. These can be both benign and malignant in nature. These can also be invasive carcinogenic in nature, which means the cancerous cells would actively spread to other parts of the body if given a chance. The treatment for invasive tumors requires the removal of both kidneys; however this can be replaced with conventional therapy at the risk of a lowered chance of full recovery and remission. Epithelial tumors can be usually treated with the help of simple surgery and follow up with chemotherapy, depending on the stage of cancer. This is found more in adult women than in teenagers and young adults.

The next type, the Germ Cell tumors are formed in the egg producing cells of the ovary. These are not as common as the first type, accounting for close to 10-15% of all ovarian cancer patients. These are also divided into benign and malignant tumors, however no intermediate or invasive form exists for this. The benign form of germ cell tumors is easily treated with simple surgery and removal of the cancerous tissue. No further treatment is deemed necessary. The malignant tumors require a more intensive form of chemotherapy and multiple medicines to keep the tumor in check and then eliminate it wholly. The treatment for this differs greatly from that of the epithelial tumors. Most cases occur with women under the age of 30.

The least common type of ovarian cancer is the Stromal tumors. They account for only 5-10% of the ovarian cancer patients. It occurs in the stromal part of the ovary, which controls the production of different kinds of sex hormones in the body. The occurrence of this kind of tumor is often marked by the production of sex steroid hormones and over production of testosterone, which leads to the masculinization of the female body and other symptoms such as balding of the hair, deepening of the voice, growth of hair over the body and an enlarged clitoris. This may also result in abnormal vaginal bleeding for post menopausal women and others. Another side effect is the early on set of puberty in young teens. The average age of women who get this is close to 25 years and usually can be treated with a degree of ease.