What Is Ovarian Cancer?

Ovarian Cancer

The body’s cells multiply uncontrollably, which is how cancer begins. Cancer can start in and spread from cells in almost any part of the body. See “What Is Cancer?” for additional information on the initiation and progression of cancer.

In contrast to the conventional wisdom, which held that ovarian cancers could only originate in the ovaries, new research indicates that a large number of ovarian cancers may actually originate in the cells located further down the fallopian tubes.

The ovaries are what?

The reproductive glands known as ovaries are unique to females. To reproduce, the ovaries create eggs, or ova. Via the fallopian tubes, the fertilized eggs leave the ovaries and enter the uterus, where they settle and grow into fetuses. The primary source of the female hormones progesterone and estrogen is the ovaries. Every side of the uterus has one ovary.

Three different types of cells make up the ovaries. Different types of tumors can arise from different types of cells:

  • The cells covering the ovary’s exterior are the source of epithelial malignancies. The majority of cancers in the ovary are epithelial cell tumors.
  • The cells that make eggs (ova) are the source of germ cell cancers.
  • The structural tissue cells that produce progesterone and estrogen and maintain the ovary together are the origin of stromal tumors. 

Certain tumors are benign, meaning they are not malignant, and they never grow outside of the ovary. Ovarian tumors that are either malignant (cancerous) or borderline (low malignant potential) have the ability to metastasis, or spread, to other regions of the body and can be lethal.

Ovarian epithelial tumors

The outer surface of the ovaries is where epithelial ovarian cancers originate. These tumors may be borderline (low malignant potential), malignant (cancer), or benign (not cancerous).

Ovarian cancers with benign epithelium

Benign ovarian epithelial tumors often do not spread and do not cause significant disease. Benign epithelial tumors come in a variety of forms, such as Brenner tumors, mucinous cystadenomas, and serous cystadenomas.

Thin-layer epithelial tumors

Borderline epithelial ovarian cancer is the term for ovarian epithelial tumors that don’t seem to be malignant when examined in a lab. The two most typical forms are mucinous carcinoma and serous carcinoma with abnormal proliferative characteristics. Prior to now, these tumors were known as tumors with low malignant potential (LMP tumors). They differ from ordinary ovarian tumors in that they do not invade the ovary’s supporting tissue, known as the ovarian stroma. If they do proliferate outside of the ovary, such as into the belly or abdominal cavity, they may do so on the surface of the abdomen rather than inside of it.

Compared to conventional ovarian malignancies, borderline tumors typically affect younger women. Compared to most ovarian cancers, these tumors develop more slowly and provide less of a threat to life.

Ovarian cancers arising from the epithelium

Carcinomas are tumors of the epithelium that are cancerous. An estimated 85% to 90% of ovarian tumors that are malignant are epithelial ovarian carcinomas. Upon examination in a lab setting, these tumor cells exhibit multiple characteristics that facilitate the classification of epithelial ovarian carcinomas into distinct subtypes. High grade and low grade tumors can be of the serous type, which is by far the most prevalent. Mucinous, endometrioid, and clear cell are the other main kinds.

  • Severe carcinomas (52 percent).
  • Cancer with clear cell (6%)
  • 6-percentage mucosal carcinoma
  • 10 percent case of endometrioid cancer

Every ovarian cancer is assigned a grade according to the degree to which the tumor cells resemble healthy tissue:

  • Grade 1 epithelial ovarian carcinomas typically have a better prognosis (outlook) and resemble normal tissue more.
  • Grade 3 epithelial ovarian carcinomas typically have a poorer prognosis and resemble normal tissue less.

Tumor type is also determined by other characteristics, such as the rate of cancer cell growth and the tumor’s response to chemotherapy:

  • Type I cancers often have slower growth rates and fewer side effects. Chemotherapy also doesn’t seem to work well on these tumors. Type I cancers include endometrioid carcinoma, mucinous carcinoma, clear cell carcinoma, and low grade (grade 1) serous carcinoma.
  • Type II cancers typically spread more quickly and develop quickly. Chemotherapy usually has a better effect on these cancers. A type II tumor is high grade (grade 3) serous carcinoma.

Other tumors that resemble ovarian epithelial cells

first peritoneal cancer

A uncommon cancer that is closely linked to epithelial ovarian cancer is called primary peritoneal carcinoma (PPC). During surgery, it appears to be the same as an abdominally distributed epithelial ovarian carcinoma. PPC similarly resembles epithelial ovarian cancer in the laboratory. This malignancy is also known as serous surface papillary carcinoma and extra-ovarian primary peritoneal carcinoma (EOPPC), which refers to the cancer outside the ovary.

The cells lining the fallopian tubes appear to be the source of PPC.

PPC is similar to ovarian cancer in that it commonly spreads throughout the surfaces of the abdomen and pelvis, making it challenging to pinpoint the specific site of the disease’s initial growth. Although women who have had their ovaries removed to prevent ovarian cancer are more at risk, this type of cancer can strike those who have not yet had their ovaries removed. It is rare for men to get this malignancy.

PPC symptoms, which include nausea, vomiting, indigestion, and changes in bowel habits, are comparable to those of ovarian cancer. Similar to ovarian cancer, PPC may also cause an increase in the blood level of the tumor marker CA-125.

The same care is typically given to women with PPC as to those with extensive ovarian cancer. This may entail a surgical procedure known as debulking, which is covered in the section on surgery, to remove as much of the cancer as possible, followed by chemotherapy akin to that prescribed for ovarian cancer. Its prognosis is probably comparable to that of ovarian cancer in general.

Fallopian tube malignancy

Like epithelial ovarian cancer, this is another uncommon malignancy. The fallopian tube, which transports an egg from the ovary to the uterus, is where it all starts. Ovarian cancer and fallopian tube cancer exhibit symptoms that are similar to PPC. Fallopian tube cancer treatment is similar to that of ovarian cancer, with a marginally better prognosis.

Germ cell tumors in ovaries

For females, germ cells typically produce ova, or eggs, and for males, sperm. The majority of germ cell tumors in the ovaries are benign, however some can be fatal and are malignant. Germ cell tumors account for less than 2% of cases of ovarian cancer. With over 90% of patients living for at least five years following diagnosis, they generally have a positive prognosis. Germ cell tumors come in a variety of subtypes. Teratomas, dysgerminomas, choriocarcinomas, and endodermal sinus tumors are the most prevalent types of germ cell cancers. Additionally, many subtypes may coexist in germ cell malignancies.


Under a microscope, teratomas (germ cell tumors) have sections that resemble the endoderm (the innermost layer), mesoderm (the middle layer), and ectoderm (the outer layer) of a growing embryo. There are two types of this germ cell tumor: immature teratoma, which is malignant, and adult teratoma, which is benign.

The most frequent ovarian germ cell tumor is by far the mature teratoma. Typically, women in their teens to forties who are of reproductive age are affected by this benign tumor. Because its lining is composed of tissue that resembles skin (dermis), it is frequently referred to as a dermoid cyst. Bone, hair, and teeth are just a few examples of the benign tissues that may be present in these tumors or cysts. Surgery to remove the cyst cures the patient, but occasionally another cyst in the opposite ovary grows back.

Among the cancers are immature teratomas. They usually affect girls and young women under the age of 18. These are uncommon malignancies that have cells in them that resemble tissues from embryos or fetuses, including connective tissue, the brain, and respiratory tracts. Surgery to remove the ovary is used to treat tumors that are substantially more mature (referred to as grade 1 immature teratomas) and haven’t spread outside of the ovary. Chemotherapy is advised in addition to surgery when the tumors have expanded outside of the ovary and/or a large portion of them are extremely young (grade 2 or 3 immature teratomas).


Although uncommon, this is the most common kind of ovarian germ cell cancer. Women in their teens and twenties are typically affected. Dysgerminomas are classified as malignant, or cancerous, tumors, although the majority do not grow or spread quickly. When they are confined to the ovary, surgical excision of the ovary cures about 75% of patients without the need for additional therapy. About 90% of patients respond well to surgery, radiation therapy, and/or chemotherapy in managing or curing their disease, even if the tumor has progressed further or if it recurs later.

Choriocarcinoma and endodermal sinus tumor (yolk sac tumor)

Typically, girls and young women are affected by these extremely rare malignancies. They typically respond quite well to treatment despite having a tendency to develop and spread quickly. Compared to choriocarcinoma that originates in the ovary, placental cancer is more common during pregnancy. Chemotherapy typically has a greater effect on placental choriocarcinomas than ovarian choriocarcinomas.

Stromal tumors of the ovary

Opportunistic stromal cell tumors account for about 1% of ovarian malignancies. About 5% of stromal tumors affect young girls, whereas more than half of stromal tumors are found in women over 50.

Symptoms of these tumors most commonly include irregular vaginal bleeding. This occurs as a result of the production of female hormones (estrogen) by many of these tumors. After menopause, these hormones may cause vaginal bleeding (similar to a period) to resume. These tumors can also induce breast development and menstruation to start before puberty in young females.

Stromal tumors produce male hormones (like testosterone) less frequently. Normal menstrual cycles may halt if the tumors create masculine hormones. They can also induce the growth of body and facial hair. Abdominal pain that comes on suddenly and intensely can be caused by a stromal tumor bleeding.

Granulosa cell tumors, the most frequent form, granulosa-theca tumors, and Sertoli-Leydig cell tumors are examples of malignant (cancerous) stromal tumors. These tumors are typically regarded as low-grade malignancies. Two benign stromal tumors are fibromas and thecomas. Over 75% of patients who have cancerous stromal tumors have a positive prognosis, having been detected at an early stage. 

Ovarian cysts

A buildup of fluid within the ovary is called an ovarian cyst. Known as functional cysts, the majority of ovarian cysts develop as a typical byproduct of ovulation, or the release of eggs. If nothing is done, these cysts typically disappear after a few months. After your subsequent menstrual cycle (period), your doctor might want to recheck the cyst to determine if it has shrunk.

When a woman isn’t ovulating (such as a woman who has gone through menopause or a girl who hasn’t begun her period), an ovarian cyst might be more problematic, and the doctor might wish to order additional testing. If the cyst is large or does not go away after a few months, the doctor may also prescribe additional tests. A tiny percentage of these cysts may be cancerous, despite the fact that the majority are benign (not cancerous). Sometimes surgery is the only method to definitively determine whether the cyst is cancerous. Based on their appearance on imaging tests, cysts that seem benign can either be watched through recurrent physical examinations and imaging tests or surgically removed.