An ovarian dermoid cyst is a benign cyst that develops on the ovaries. It is a fluid-filled sac that contains tissues such as teeth, skin, hair, and fat. People may also refer to them as mature cystic teratomas.

Ovarian dermoid cysts are the most common type of ovarian teratoma, which is a type of mass, or tumor, that develops on the ovaries.

This article explains what an ovarian dermoid cyst is, as well as the symptoms a person may experience, how these cysts develop, and how doctors treat them.

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An ovarian dermoid cyst is a germ cell tumor that develops on the ovaries. Although they are benign, they can become cancerous in rare circumstances.

A 2017 article states that ovarian dermoid cysts mostly consist of sebaceous material that is liquid at body temperature and semisolid at room temperature. They also contain solid matter, including:

  • bone
  • teeth
  • hair
  • fat

According to a 2022 article, the size of these cysts can vary from very small, to larger than 39 centimeters (cm). In 80% of cases, they measure 10 cm or less.

Ovarian dermoid cysts are typically slow growing. The article’s authors note that they have a growth rate of 1.8 millimeters (mm) per year in those who have not experienced menopause.

They most commonly affect the ovary on the right side, but in 12% of cases, they can develop on both ovaries.

They most commonly affect females ages 20–40 years.

A 2016 article states that ovarian dermoid cysts account for 70% of all benign ovarian masses affecting females in their reproductive years. They also account for 20% of benign ovarian masses in postmenopausal people.

Most ovarian dermoid cysts do not cause symptoms unless a complication develops. However, if symptoms are present, the most common symptom that people report is lower abdominal pain.

As the cyst grows larger, people may notice an increase in the size of their abdomen and urinary or gastrointestinal symptoms.

If the cyst is advanced, people may also experience:

The Office on Women’s Health states that cysts that develop on the ovaries can cause:

  • abdominal pressure
  • bloating
  • abdominal swelling
  • lower abdominal pain

Other less common symptoms can include:

Dermoid cysts are present at birth. This is because they develop during the development of an embryo.

They occur when elements of the ectodermal layer become trapped as the embryo develops. The ectoderm is a layer of cells that covers the outside of the body of an embryo. Tissues such as skin, hair, teeth, and nails, develop from this layer of cells.

The cysts become filled with hair, teeth, fat, and bone as the trapped cells grow into mature tissue.

However, scientists are not sure why this developmental anomaly happens.

Some potential complications include:

  • Rupturing of the cyst: Although uncommon, ovarian dermoid cysts can rupture. If the contents of the cyst leak into the peritoneal cavity, it can lead to chronic peritonitis. This is the inflammation of the lining of the abdominal wall. If the contents of the cyst leak into the intestine or rectum, they may leave the body via the anus.
  • Ovarian torsion: This is when the cyst twists the ligaments that hold the ovaries in place. This can cut off the blood flow to the ovary and the fallopian tube.
  • Infection: The chance of infection is approximately 1–4%. In severe, cases, this can cause the cyst to rupture.
  • Malignant transformation: Ovarian dermoid cysts are almost always benign. However, they can become malignant in rare cases.

If a torsion or rupture occurs, a person may experience:

  • sudden and severe abdominal pain
  • nausea
  • vomiting

A doctor often discovers the presence of an ovarian dermoid cyst during examinations for other conditions.

To begin with, a doctor will perform an initial assessment. This involves:

  • checking a person’s vitals
  • performing a pelvic and abdominal physical exam
  • taking a detailed history
  • ordering a complete blood count
  • ordering a complete metabolic panel
  • ordering a pregnancy test

They may also order imaging tests such as an ultrasound or MRI scan.

A 2022 article notes that treatment plans for ovarian dermoid cysts depend on:

  • a person’s symptoms
  • a person’s desire to remain able to conceive
  • the size of the tumor
  • the characteristics of the tumor as seen on the ultrasound
  • the potential involvement of surrounding tissues
  • the chance that the cyst will become malignant

A healthcare professional may recommend surveillance if a person is pregnant, or if the cyst is a small size and is not causing any symptoms. This is also the case if the cyst measures less than 6 cm in those who wish to become pregnant.

In other cases, surgery may be the best course of action. For those with cysts measuring less than 5 cm, a surgeon may perform a laparoscopic cystectomy. This involves surgically removing the cyst instead of the entire ovary.

An oophorectomy, which is the surgical removal of the ovary, may be necessary if the cysts measure more than 5–6 cm and have affected the entire ovary.

If a pregnant person requires surgery, a 2018 review found that laparoscopic surgery is safe and successful.

Here are some frequently asked questions regarding ovarian dermoid cysts:

Is an ovarian dermoid cyst a fetus?

An ovarian dermoid cyst is not a fetus. They are present at birth as they develop as an embryo grows.

Ovarian dermoid cysts are benign cysts that contain sebaceous material alongside mature tissue, such as hair, fat, and teeth.

Do ovarian dermoid cysts always need to be removed?

Treatment is not always necessary. Providing the cyst is small enough and not causing any symptoms, a doctor may recommend surveillance as a treatment option.

However, if the cyst becomes large, causes symptoms, or results in complications, surgical removal is likely to be necessary.

People should contact a doctor if the cyst is causing symptoms, such as lower abdominal pain.

If people experience symptoms of any complications, they should seek prompt medical attention.

These symptoms can include:

  • sudden and severe abdominal pain
  • nausea
  • vomiting

Ovarian dermoid cysts are a type of benign cyst that develops on the ovaries. It contains sebaceous material along with tissues, such as teeth, hair, and bones.

They occur during fetal development when certain cells become trapped. These cells then grow into mature tissue cells, resulting in the presence of hair and teeth.

Ovarian dermoid cysts are unlikely to cause symptoms. However, if symptoms do occur, a person may experience lower abdominal pain.

A doctor may recommend surveillance if the cyst is small and not causing any symptoms. However, surgical removal may be necessary.

People should seek prompt medical help if complications develop.