A dermoid cyst is an enclosed sac near the surface of the skin that forms during a baby’s development in the uterus.

The cyst can form anywhere in the body. It may contain hair follicles, skin tissue, and glands that produce sweat and skin oil. The glands continue to produce these substances, causing the cyst to grow.

Dermoid cysts are common. They’re usually harmless, but they need surgery to remove them. They don’t resolve on their own.

Dermoid cysts are a congenital condition. This means they’re present at birth.

Dermoid cysts tend to form near the surface of the skin. They’re often noticeable soon after birth. Some may develop deeper inside the body as well. This means diagnosing them may not happen until later in life.

The location of a dermoid cyst determines its type. The more common types are:

Periorbital dermoid cyst

This type of dermoid cyst usually forms near the right side of the right eyebrow or the left side of the left eyebrow. These cysts are present at birth. However, they may not be obvious for months or even a few years after birth.

The symptoms, if any, are minor. There’s little risk to a child’s vision or health. However, if the cyst becomes infected, prompt treatment of the infection and surgical removal of the cyst is essential.

Ovarian dermoid cyst

This kind of cyst forms in or on an ovary. Some types of ovarian cysts are related to a woman’s menstrual cycle. But an ovarian dermoid cyst has nothing to do with the ovary’s function.

Like other kinds of dermoid cysts, an ovarian dermoid cyst first develops before birth. A woman may have a dermoid cyst on an ovary for many years until it’s discovered during a pelvic exam.

Spinal dermoid cyst

This benign cyst forms on the spine. It doesn’t spread elsewhere. It may be harmless and present no symptoms.

However, this kind of cyst may press against the spine or spinal nerves. For that reason, it should be surgically removed.

Many dermoid cysts have no obvious symptoms. In some of these cases, symptoms develop only after the cyst has become infected or has grown significantly. When symptoms are present, they may include the following:

Periorbital dermoid cyst

Cysts near the surface of the skin can swell. This may feel uncomfortable. The skin may have a yellowish tint.

An infected cyst can become very red and swollen. If the cyst bursts, it can spread the infection. The area around the eye may get very inflamed if the cyst is on the face.

Ovarian dermoid cyst

If the cyst has grown large enough, you may feel some pain in your pelvic area near the side with the cyst. This pain may be more pronounced around the time of your menstrual cycle.

Spinal dermoid cyst

Symptoms of a spinal dermoid cyst usually begin once the cyst has grown large enough that it starts to compress the spinal cord or the nerves in the spine. The cyst’s size and location on the spine determine which nerves in the body are affected.

When symptoms occur, they can include:

  • weakness and tingling in the arms and legs
  • difficulty walking
  • incontinence

Doctors can see dermoid cysts even in developing babies not yet born. However, it’s not clear why some developing embryos have dermoid cysts.

Here are the causes for the common types of dermoid cysts:

Periorbital dermoid cyst causes

A periorbital dermoid cyst forms when the skin layers don’t grow together properly. This allows skin cells and other materials to collect in a sac near the skin’s surface. Because the glands that are in the cyst continue to secrete fluids, the cyst continues to grow.

Ovarian dermoid cyst causes

An ovarian dermoid cyst or a dermoid cyst that grows on another organ also forms during embryonic development. It includes skin cells and other tissues and glands that should be in the layers of a baby’s skin, not around an internal organ.

Spinal dermoid cyst causes

A common cause of spinal dermoid cysts is a condition called spinal dysraphism. It occurs early in embryonic development, when part of the neural tube doesn’t close completely. The neural tube is the collection of cells that will become the brain and spinal cord.

The opening in the neural cord allows a cyst to form on what will become the baby’s spine.

Diagnosing a periorbital dermoid cyst or a similar cyst near the skin’s surface in the neck or chest can usually be done with a physical exam. Your doctor may be able to move the cyst under the skin and get a good sense of its size and shape.

Your doctor may use one or two imaging tests, especially if there’s concern that the cyst is near a sensitive area, such as the eye or the carotid artery in the neck. These imaging tests can help your doctor see exactly where the cyst is located and whether damage to a sensitive area is a high risk. The imaging tests your doctor may use include:

  • CT scan. A CT scan uses a special X-ray and computer equipment to create three-dimensional, layered views of tissue inside the body.
  • MRI scan. An MRI uses a powerful magnetic field and radio waves to create detailed images inside the body.

Your doctor will use an MRI and CT scan to diagnose spinal dermoid cysts. Before treating a cyst, it’s critical your doctor knows just how close it is to nerves that could potentially be harmed during surgery.

A pelvic exam may reveal the presence of an ovarian dermoid cyst. Another imaging test your doctor may use to identify this type of cyst is called a pelvic ultrasound. A pelvic ultrasound uses sound waves to create images. The test uses a wandlike device, called a transducer, that’s rubbed across the lower abdomen to create images on a nearby screen.

Your doctor may also use a transvaginal ultrasound. During this test, your doctor will insert a wand into the vagina. Like with the pelvic ultrasound, images will be created using sound waves emitted from the wand.

Regardless of its location, the only treatment option for a dermoid cyst is surgical removal. There are several key factors to consider before surgery, especially if the cyst is treated in a child. These include:

  • medical history
  • symptoms
  • risk or presence of an infection
  • tolerance for an operation and the medications that are required postsurgery
  • severity of the cyst
  • parental preference

If surgery is decided, here’s what to expect before, during, and after the procedure:

Before surgery

Follow the directions your doctor gives you before surgery. They’ll let you know when you need to stop eating or taking medications before surgery. Since general anesthesia is used for this procedure, you’ll also need to make transportation arrangements to go home.

During surgery

For periorbital dermoid cyst surgery, a small incision can often be made near an eyebrow or hairline to help hide the scar. The cyst is carefully removed through the incision. The entire procedure takes about 30 minutes.

Ovarian dermoid surgery is more complicated. In some cases, it can be done without removing the ovary. This is called an ovarian cystectomy.

If the cyst is too large or there’s been too much damage to the ovary, the ovary and cyst may have to be removed together.

Spinal dermoid cysts are removed with microsurgery. This is done using very small instruments. During the procedure, you’ll lie face down on an operating table while your surgeon works. The thin covering of the spine (dura) is opened to access the cyst. Nerve function is monitored carefully throughout the operation.

After surgery

Some cyst surgeries are done as outpatient procedures. This means you can go home the same day.

Spinal surgeries may require an overnight stay in the hospital to watch for any complications. If a spinal cyst has too strong of an attachment to the spine or the nerves, your doctor will remove as much of the cyst as is safely possible. The remaining cyst will be monitored regularly after that.

Recovery after surgery can take at least two or three weeks, depending on the location of the cyst.

Usually, untreated dermoid cysts are harmless. When they’re located in and around the face and neck, they can cause noticeable swelling under the skin. One of the main concerns with a dermoid cyst is that it can rupture and cause an infection of the surrounding tissue.

Spinal dermoid cysts that are left untreated may grow large enough to injure the spinal cord or nerves.

While ovarian dermoid cysts are usually noncancerous, they can grow quite large. This can affect the position of the ovary in the body. The cyst can also lead to a twisting of the ovary (torsion). Ovarian torsion can affect blood flow to the ovary. This may affect the ability to get pregnant.

Because most dermoid cysts are present at birth, you’re unlikely to develop one later in life. Dermoid cysts are usually harmless, but you should discuss the pros and cons of surgical removal with your doctor.

In most cases, cyst removal surgery can be done safely with few complications or long-term problems. Removing the cyst also removes the risk of it rupturing and spreading an infection that can become a more serious medical problem.