Ovarian cysts are sacs that form in an ovary or on the surface of an ovary. While many are noncancerous, some could be malignant. In both cases, ovarian cysts may only cause noticeable symptoms as they grow.

Ovaries are small organs located deep within the pelvis. Eggs grow inside them, within a sac or follicle. An egg is released from its sac into one of your fallopian tubes during ovulation. After that, the sac typically dissolves.

But sometimes, the sac can remain, fill with fluid, and develop into a cyst. Cysts that form in or around your ovaries often go unnoticed. They may cause only mild symptoms or no noticeable symptoms at all.

About 20% of people with ovaries develop them at some point during their reproductive years.

While not common, some ovarian cysts are malignant, or cancerous. Ovarian cancer tends to affect people who have already gone through menopause.

Fortunately, most ovarian cysts are benign, or not cancerous. A doctor’s recommended treatment plan depends on your type of ovarian cyst or tumor and your symptoms. Often, they may not require any treatment.

Cysts that form during your menstrual cycle are called functional cysts. There are two types of functional ovarian cysts: follicle and corpus luteum cysts. Other health conditions may also lead to ovarian cysts.

Follicle cysts

Follicle cysts form when an egg fails to break out of its sac. These types of cysts usually disappear on their own within 1 to 3 months.

Corpus luteum cysts

Corpus luteum cysts develop when a sac closes up after releasing its egg, allowing fluid to accumulate inside. These cysts usually resolve on their own in a few weeks.

Polycystic ovary syndrome

Sometimes, eggs mature in their sacs but are never released. As your menstrual cycle repeats, the sacs may grow larger and develop into multiple cysts. This condition is known as polycystic ovary syndrome (PCOS).

Other types

Other types of ovarian cysts and tumors can also occur. For example:

  • Ovarian endometriomas can develop if you have endometriosis. This condition causes cells similar to the endometrial tissue lining your uterus to grow in other areas of your body. If these cells attach to one of your ovaries, an ovarian endometrioma can form.
  • Ovarian cystadenomas are liquid-filled cysts that develop from cells on the surface of your ovary. While most are benign, some cystadenomas are cancerous.
  • Ovarian dermoid cysts, or teratomas, are made up of various cell types. They’re a type of ovarian germ cell tumor. Usually, these tumors are benign, but occasionally they can be malignant.

It’s most common for these types of benign cysts to develop during reproductive years or after starting menstruation. It’s less common to develop an ovarian cyst before you experience your first menstrual period or after menopause. If it does happen, a doctor may want to investigate further.

Read more: Ovarian cysts: Types, symptoms, and treatment »

It’s possible to have an ovarian cyst and not realize it. Symptoms can range from mild to severe. They can include:

  • abdominal bloating and pressure
  • painful intercourse
  • frequent urination
  • menstrual irregularities
  • unusual hair growth
  • fevers

Like noncancerous ovarian cysts, cancerous tumors sometimes cause no or only minor symptoms at first. They’re typically hard to feel, even during a physical exam. That’s why it’s difficult to detect early stage ovarian cancer.

Symptoms of ovarian cancer are similar to those of ovarian cysts. They can include:

  • abdominal swelling or bloating
  • abdominal pressure and pain
  • feeling overstuffed or having trouble eating
  • frequent or urgent urination
  • menstrual irregularities
  • painful intercourse

If you have symptoms associated with ovarian cysts or ovarian cancer, see a doctor or gynecologist as soon as possible.

Sometimes, you may not know that you have an ovarian cyst or tumor until a doctor detects it during a routine pelvic exam. In other cases, you might experience signs or symptoms first, and a doctor may perform imagining tests to reveal an ovarian cyst or tumor.

If you notice signs or symptoms, make an appointment with a doctor.

If a doctor suspects you have an ovarian cyst or tumor, they may order tests to examine your ovaries. These exams may include:

A doctor may also want to test your blood for CA-125, a tumor marker. High levels of CA-125 may indicate the presence of ovarian cancer.

A doctor may also recommend additional imaging tests, like an MRI, to determine if an ovarian cyst or tumor is benign or malignant.

A doctor may also perform a biopsy to confirm or rule out ovarian cancer. They will collect a sample of the cyst or tumor for analysis under a microscope. This will help them determine if it’s cancerous.

In many cases, ovarian cysts resolve on their own without treatment. If you have an ovarian cyst that doesn’t go away on its own or is causing you pain, a doctor may recommend surgical removal of the cyst. A surgeon can usually accomplish this without damaging your ovary or affecting fertility.

If you receive a diagnosis of ovarian cancer, an oncologist may recommend one or a combination of the following treatment options:

  • chemotherapy
  • radiation
  • surgery
  • hormone therapy
  • targeted drug therapy

There’s no known way to prevent ovarian cysts.

Your long-term outlook will depend on your diagnosis. Most ovarian cysts resolve within a few months, often without treatment.

The outlook for ovarian cancer varies, depending on its stage and type. People who receive an earlier diagnosis have a greater 5-year survival rate.

It’s important to report unusual symptoms to a doctor immediately. The sooner you know what’s going on, the better. If you have ovarian cancer, your outlook will be better if it’s diagnosed and treated in its early stages.

Ovarian cancer is rare in younger women. According to the National Cancer Institute, the median age of a diagnosis is 63. Your risk depends on your family history of ovarian cancer or if you carry certain genetic mutations. The lifetime risk of dying from ovarian cancer for women is about 1 in 108.

Benign ovarian cysts can be relatively common and often do not require treatment unless they cause pain.

While less common, ovarian cysts can be cancerous. Detecting ovarian cancer early may improve your survival rate.

If you experience symptoms of an ovarian cyst, such as abdominal pressure and pain or painful intercourse, consider speaking with a doctor as soon as possible. They can order exams to rule out or diagnose ovarian cancer.