What Is a Dermoid Cyst in the Ovary?

Ovarian dermoid cysts (also called mature cystic teratomas) are a type of germ cell tumor (growths of cells that form from reproductive cells). These cysts are fluid-filled sacs that contain tissues meant to develop in other parts of the body.

Tissues in ovarian dermoid cysts can include hair, teeth, skin, muscle, and bone. Dermoid cysts in ovaries typically are present at birth but may not grow or become symptomatic for many years. Around 2% become malignant (cancerous).

Ovaries are part of the female reproductive system. They produce and store eggs (ova). The ovaries also manufacture the hormones estrogen and progesterone. These hormones regulate ovulation (release of the egg from the ovary) and the menstrual cycle.

There are several types of ovarian cysts. The most common type is functional cysts that develop in response to ovulation. Dermoid cysts in ovaries are far less common, but they are the most common type of benign ovarian tumor.

This article will explain how dermoid cysts in ovaries form, as well as their symptoms, treatments, and potential complications.

Ovarian Dermoid Cyst Symptoms and Complications

Dermoid cysts in the ovaries may remain asymptomatic (have no symptoms). In some instances, they may enlarge and cause symptoms, including:

• Pelvic pain
• Palpable mass in the lower abdomen or pelvis
• Changes in menstruation
• Trouble with urination
• Gastrointestinal distress

Symptoms may also result from dermoid cyst complications, such as ovarian cyst rupture (a cyst that bursts open) or ovarian torsion (the ovary twists around its supporting tissues and blood vessels). In rare cases, malignant transformation in a cyst may occur, turning a benign cyst into a cancerous one.

Ovarian torsion or rupture can cause severe, intense pelvic or abdominal pain. Other symptoms of complications can include:

• Nausea
• Vomiting
• Fever
• Abdominal bloating or feeling of fullness
• Vaginal bleeding or spotting
• Feeling faint
• Dizziness
  

When combined with severe pain, these symptoms may indicate a medical emergency. Acute pelvic or abdominal pain should always be brought to a healthcare provider's attention.

Causes

Dermoid cysts develop prenatally, in embryos. The underlying cause of ovarian dermoid cysts is not completely known or understood.

Dermoid cysts are composed of two or three embryonic germ layers. Germ layers are groups of cells that differentiate to form all of the body’s organs and tissues. The three germ layers are:

• Ectoderm: Outermost embryonic layer
  
• Mesoderm: Middle embryonic layer
• Endoderm: Innermost embryonic layer

Dermoid cysts are caused by a problem with the cell differentiation process. That’s why ovarian dermoid cysts contain tissues that don’t belong in an ovary, such as hair, teeth, fat, or bone.

Diagnosis

Small, asymptomatic ovarian dermoid cysts may be discovered incidentally during routine ultrasound exams, such as those given during pregnancy. They may also be discovered during delivery via cesarean section (C-section).

If an ovarian dermoid cyst is found or suspected, a physical exam will be done. Your healthcare provider will pay particular attention to your pelvis and abdomen, to check for tenderness, pain, and swollen areas.

Blood and urine tests may be given to check for an alternative diagnosis. Ovarian dermoid cysts don't have diagnostic tumor markers that can be seen in a blood sample.

Imaging tests of the ovary may be done, such as:

• Ultrasound: Uses sound waves to produce an image
• Computed tomography (CT) scan: Uses X-rays and a computer to produce a cross-sectional image
• Magnetic resonance imaging (MRI): Uses magnetic fields and radio waves to generate a detailed image
  

If malignancy is suspected, surgical removal will be recommended.

Treatment

Small, asymptomatic ovarian dermoid cysts don't usually require treatment. Your healthcare provider may recommend a consistent schedule of follow-up exams to look for changes in the cyst that might warrant the need for its removal.

A dermoid cyst smaller than 6 centimeters (cm) may remain intact, provided it doesn’t grow by more than 2 cm annually. Ovarian cyst surgery may be avoided, if possible, especially if you're of reproductive age and hoping for pregnancy.

Cysts that cause symptoms should, however, be removed surgically. This eliminates concerns about rupture or torsion.

Smaller cysts may be removed through a surgical procedure called a laparoscopic cystectomy. This procedure removes the cyst and leaves the rest of the ovary intact.

If the dermoid cyst is larger than 5 cm–6 cm, an oophorectomy (surgical removal of an ovary) may be recommended. This is likely to be considered if the cyst distorts the ovary's structure.

Surgical removal is usually done if the cyst is malignant, followed by chemotherapy. An oophorectomy is usually recommended.

Prognosis

Ovarian dermoid cysts are benign in 98% to 99% of all cases. After the removal of a benign cyst, there is a small risk of regrowth (4% in one study).

If a dermoid cyst in an ovary is malignant, your prognosis will be determined by the cyst's growth pattern, invasiveness, and stage. The cyst's response to treatment is also a significant prognostic factor.

Summary

Dermoid ovarian cysts are usually benign tumors that develop from reproductive cells that would form different tissues in an embryo. They may have no symptoms or they can be painful. They can rupture or produce ovarian torsion, which are medical emergencies.

Diagnosis is usually done with imaging. Observation or watchful waiting may be the preferred course. If a dermoid ovarian cyst is larger or producing symptoms, it may be removed surgically.

A Word From Verywell

Knowing you have an ovarian dermoid cyst can be concerning. Try to remember that the vast majority of dermoid cysts never become cancerous. Torsion, the most common complication, can be avoided with surgical cyst removal. Most dermoid cysts remain asymptomatic and won't impact fertility in themselves.

If you have an ovarian dermoid cyst, being proactive is important. Let your healthcare provider know of any acute or chronic symptoms you may feel. Monitoring the cyst with regular ultrasounds per your healthcare provider's recommendations will help you keep on top of potential changes and help to avoid complications.