Usually, epithelial ovarian tumors are benign, they don't spread and do not cause a serious illness. Among the types of benign epithelial tumors, we can mention serous adenomas, mucinous adenomas, and Brenner tumors.

There are some epithelial ovarian tumors that do not appear clearly under the microscope to be cancerous. These are called tumors of low malignant potential, and it is known that they differ from typical ovarian cancers because they do not grow into the supporting tissue of the ovary. These tumors grow slowly, and are less dangerous than most ovarian cancers.

Cancerous epithelial tumors, also called carcinomas represent 85% to 90% of the ovarian cancers. The epithelial ovarian carcinomas can be classified because of some features that can be seen under the microscope into serous, mucinous, endometrioid, and clear cell types. The most common type is the serous. There also are undifferentiated epithelial ovarian carcinomas, which tend to grow and spread more quickly and do not look like any of these 4 subtypes. Epithelial ovarian carcinomas are classified by cell type and are given a grade on a scale of 1, 2, or 3. Epithelial ovarian carcinomas that are given grade 1 look like a normal tissue and tend to have a better prognosis. Grade 3 epithelial ovarian carcinomas look less like a normal tissue, and tend to have a worse prognosis.

Also called extra-ovarian, the primary peritoneal carcinoma is a cancer closely related to epithelial ovarian cancer. It develops in cells from the peritoneum but it is difficult to tell exactly where the cancer first started because it tends to spread along the surfaces of the pelvis and abdomen.The symptoms provoked by this cancer are similar to those of ovarian cancer. These symptoms include nausea, vomiting, abdominal pain or bloating, indigestion, and a change in bowel habits.The treatment consists in surgery, which will remove as much of the cancer as possible, and after that chemotherapy follows.

The germ cell tumors represent about 5% of ovarian cancers, have several subtypes, and usually are benign, although some can be life-threatening. Some of the most usual germ cell tumors are teratoma, endodermal sinus tumor, dysgerminoma and choriocarcinoma.

Teratoma has two forms: a benign form called mature teratoma, and a cancerous form called immature teratoma. The mature teratoma, also called a dermoid cyst usually affects women of reproductive age and is the most common ovarian germ cell tumor. These tumors also contain a variety of other benign tissues that may resemble adult respiratory passages, bone, nervous tissue, teeth, and other tissues. Surgical intervention is needed, in order to remove the cyst.

Immature teratomas resemble embryonic or fetal tissues such as connective tissue, respiratory passages, and brain, are rare cancers, and appear usually in girls younger than 18. If the tumor has not spread beyond the ovary and is not very immature, surgical removal of the ovary is needed, but if it had spread beyond the ovary or it looks very immature, surgical removal of the ovary and chemotherapy is needed.
Dysgerminoma is the most common ovarian cancer of germ cells, affects women in their teens and twenties, is considered malignant, but usually, does not grow or spread very quickly. If the tumor is limited to the ovary, the ovary must be surgically removed, and when the tumor has spread further, chemotherapy is needed in addition to surgery.Endodermal sinus tumor and choriocarcinoma tend to grow and spread rapidly but are very sensitive to chemotherapy, they are very rare and affect girls and young women.

Stromal tumors usually appear in women over age 50, but can occur in young girls as well. Some of these tumors produce female hormones, or, more rarely male hormones, can cause vaginal bleeding to start again after menopause, or can cause menstrual periods and breast development in young girls. Thecomas and fibromas are benign stromal tumors, and granulosa cell tumors, granulosatheca tumors, and Sertoli-Leydig cell tumors are some types of malignant stromal tumors.

It is known that as a result of ovulation, there can appear cysts, which are called functional cysts and are completely normal. In about 1 to 3 months, these cysts shrink, and if you have this type of cysts, it is good to do a check after 1-3 months to see if the cyst became smaller. In some cases, it is possible that the doctor will prescribe birth control pills, to stop ovulation and in this way the forming of the cysts will stop.
As ways of treating the benign cysts, we can mention : observation, medications or surgical removal.

The fallopian tube cancer is extremely rare, shows symptoms similar to those that appear in women with ovarian cancer, and there can also appear more pelvic pain. In what concerns the treatment and outlook, it is similar to that for ovarian cancer.