Most women develop ovarian cysts at some point during their lifetime. Some cyst types can become large in size. Treatment for large cysts may include surgery.

Ovarian cysts are fluid-filled sacs that can form in or on your ovaries. Most ovarian cysts are benign (noncancerous). They typically form due to hormonal changes, pregnancy, or health conditions like endometriosis.

The most common type of ovarian cyst, known as a functional or ovulatory cyst, develops every month when you ovulate. They aren’t usually harmful, have no symptoms, and typically go away on their own within a few weeks or months.

But this isn’t the only type of cyst that can develop in or on your ovaries. Some other types are less common.

This article will look at the different types of ovarian cysts, the typical size of each, as well as potential treatment options.

There are different types of ovarian cysts, each with unique causes and characteristics. The size of an ovarian cyst can also vary depending on what type of cyst it is.

Size is also one of several factors that can help determine whether a cyst needs to be surgically removed. Generally speaking, surgery isn’t recommended for ovarian cysts unless they’re large in size, cause symptoms, or are cancerous. A doctor may also recommend removal if you have a family history of certain types of cancer.

Let’s look at each type of ovarian cyst in more detail as well as the typical size of each.

Functional cysts form when your menstrual cycle follows its normal pattern. They typically go away on their own. In some cases, though, the cyst can continue growing. Two examples of functional cysts include the following:

  • Follicular: Follicular cysts form when a follicle, a small sac that stores an egg and produces estrogen, doesn’t release the egg during ovulation. Instead, the follicle continues growing, producing a follicular cyst. These cysts are typically larger than 2.5 centimeters (cm) which is larger than 0.98 of an inch in diameter.
  • Corpus luteum: Corpus luteum cysts can form when the empty follicle sac doesn’t shrink after ovulation. Instead, the sac becomes sealed off and fills with fluid, leading to a corpus luteum cyst. These cysts typically grow to about 3 cm (about 1.18 inches).

However, some may reach sizes larger than 10 cm (about 4 inches).

Dermoid cysts are also called teratomas. They can contain different tissue types, such as skin, hair, and fat. Dermoid cysts are often asymptomatic, although they may cause symptoms and complications if they become large.

These cysts are a type of ovarian tumor. They’re almost always benign and are often present from birth. Dermoid cysts can grow during reproductive years.

These cysts often grow slowly, progressing at about 1.8 mm (about 0.07 inches) per year.

Dermoid cysts do have the potential to become large, though. Older case studies have reported that some dermoid cysts can grow more rapidly, between 8 and 25 mm (0.3 to about 1 inch) per year.

In rare cases, giant dermoid cysts over 15 cm (about 6 inches) in diameter have been reported.

Cystadenomas are benign tumors that develop on the surface of your ovaries. They can be filled with a watery or mucus-like liquid.

When viewed using ultrasound, a cystadenoma often looks like a functional cyst. However, while functional cysts typically go away after several menstrual cycles, a cystadenoma will grow.

Cystadenomas can also become quite large. While some can be on the smaller side, around 1–3 cm (roughly 0.5–1 inch), some can grow up to 30 cm (almost a foot).

Endometriomas form due to endometriosis. Endometriosis is a condition where the cells of the uterine lining grow outside of the uterus. This tissue can attach to the surface of your ovary and form a cyst.

It’s estimated that between 17 and 44% of people with endometriosis will have an endometrioma. These cysts are sometimes called chocolate cysts because they can contain thick, dark blood that gives them a brownish color.

Endometriomas are typically small, but like other cysts, they can come in various sizes.

Many times, ovarian cysts don’t have any symptoms. When symptoms are present, they can include:

  • pain on one side of your lower abdomen, which may be dull or sharp
  • a feeling of fullness or pressure in your abdomen
  • abdominal bloating or swelling

Other less common symptoms can include:

Complications from ovarian cysts are rare. Sometimes a cyst can break open (rupture), leading to sharp pain or bleeding.

In other cases, the ovary can become twisted around surrounding tissues (torsion), potentially cutting off the blood supply to the ovary.

Be sure to seek prompt medical attention if you experience any of the following symptoms:

Not all ovarian cysts require treatment, and many go away on their own. Because of this, a doctor may recommend a period of watchful waiting to monitor your cyst to see if it goes away after one or two menstrual cycles.

If you experience discomfort from an ovarian cyst, a doctor may suggest over-the-counter (OTC) pain medications to help with pain relief. Examples include:

Sometimes, an ovarian cyst may require surgical removal. This may be necessary when a cyst:

  • is large or continues to grow
  • doesn’t go away on its own after several menstrual cycles
  • causes acute pain
  • appears abnormal or malignant (cancerous) via ultrasound

Surgical removal of ovarian cysts is often accomplished using minimally invasive methods like laparoscopy. However, more invasive open surgery may be necessary when a cyst is very large, or cancer is suspected.

A doctor may prescribe a hormonal contraceptive if you often get functional cysts. While this medication can help prevent new functional cysts from forming, it won’t shrink an existing cyst.

The following includes frequently asked questions about ovarian cysts.

What size ovarian cyst is worrisome?

If you have an ovarian cyst that measures 10 cm (about 4 inches), doctors may decide to remove it. But other factors, such as its appearance and growth rate, may also indicate a need for prompt treatment.

Is a 4 cm (1.5 inch) cyst on an ovary large?

Ovarian cysts can vary significantly by size, depending on the type. Many people with ovaries develop functional cysts during their menstrual cycle. These cysts are typically larger than 2.5 cm (0.98 of an inch). Some ovarian cysts may be 10 cm (about 4 inches).

What is considered a big ovarian cyst?

Doctors may consider an ovarian cyst large if it measures 10 cm (about 4 inches) or greater. However, this can also depend on the type of cyst. If the cyst gets larger or doesn’t go away on its own, a doctor may recommend diagnostic tests.

What is a normal ovarian cyst size?

People with ovaries typically develop functional cysts during their menstrual cycle, often measuring larger than 2.5 cm (0.98 of an inch). These cysts usually go away on their own in time. If the cysts do not go away or grow during the next few menstrual cycles, a doctor may recommend additional tests to determine the type of cyst.

Most people with ovaries have ovarian cysts at some point during their lifetime. In fact, functional ovarian cysts are a normal part of your menstrual cycle. These cysts typically don’t have any symptoms and usually go away within a few weeks.

Some other types of cysts, like dermoid cysts, cystadenomas, and endometriomas, are much less common. These cysts can continue to grow and become large.

Most cysts don’t need to be surgically removed. However, surgery may be recommended for cysts that are large, don’t go away on their own, or appear abnormal by ultrasound.