An osteoma is a benign bone tumor that typically forms on the skull. Depending on where they develop, osteomas can sometimes cause symptoms such as headaches or sinus infections.

Although osteomas tend to form on the skull, they can also develop on the long bones of the body, such as the shin and thigh bones. Osteomas that occur on the long bones of the body are called osteoid osteomas.

This article will cover the different types of osteoma, as well as their symptoms, causes, and potential treatments.

According to a 2013 article, there are three recognized types of osteoma:

  • Compact: These are made of very dense bone material.
  • Spongy: These are similar to normal bone and often include bone marrow.
  • Combined or mixed: These growths have both compact and spongy qualities.

Osteomas can occur nearly anywhere on the bones in the skull. According to the 2013 study, they are common in the jawbone and the paranasal sinuses.

In most cases, osteomas do not cause symptoms. In fact, a person may not realize that they have a growth until a doctor examines the sinuses or the skull due to other health concerns the person has.

The size and location of the osteoma may contribute to its potential symptoms. For example, smaller growths are less likely to cause symptoms. Larger growths are more likely to cause symptoms based on their location.

The following are some potential locations of osteomas:

  • Near the sinuses: An osteoma near the sinuses could cause an obstruction, which can prevent mucus from draining and lead to a sinus infection.
  • Near the eye: An osteoma near the eye may cause the eye to protrude. This is known as proptosis.
  • Forehead or skull: An osteoma on the forehead or skull may cause headaches.
  • Jawbone: An osteoma on the jawbone can cause facial pain or pain when moving the mouth.
  • Ear: An osteoma in the ear could cause temporary hearing loss. This will usually resolve with treatment.
  • Long bones: Osteomas on the long bones in the body are called osteoids. These can appear on the tibia (shin bone) and femur (thigh bone).

According to one 2010 review, doctors do not yet fully understand what causes osteomas.

They may be a result of the body reacting to illness or injury.

In rare cases, osteoma is associated with Gardner’s syndrome. Gardner’s syndrome is a rare condition that causes colorectal polyps and different types of benign and malignant tumor.

Osteomas do not always require treatment. According to Stanford Medicine, when treatment is necessary for an osteoma on the skull, a doctor can use endoscopic procedures — which, in this case, refers to the insertion of specialized instruments through the person’s nasal cavity.

If the osteoma occurs near the surface of the skin, doctors can often create small incisions in the skin to remove the growth. Large growths may require more invasive techniques, however.

One 2017 study points out that a doctor may also recommend percutaneous radiofrequency ablation to treat osteoid osteomas. This technique uses radiofrequency waves to destroy the osteoma and prevent it from growing back.

According to Stanford Medicine, a CT scan of the bones is often enough to diagnose osteoma. In many cases, a biopsy is not necessary.

However, there are several other ways to diagnose an osteoma, including MRI and X-ray scans.

Osteomas can sometimes cause complications. These include:

Osteomas are benign, meaning that they are not cancerous and will not spread to nearby tissue.

Learn about the differences between a cyst and a tumor here.

A person may not realize that they have osteoma. Instead, a doctor may discover the growth during a routine examination.

In other cases, a person may experience symptoms such as pain or a visible growth under the skin. A person should talk to a doctor about these symptoms.

In some cases, such symptoms may be the result of another underlying condition that a doctor can diagnose.

Symptoms are often not present with osteomas. When symptoms do not occur, treatment may not be necessary, and a doctor may simply watch the condition over time.

When treatment is necessary, it often involves removing the growth.

Osteomas are benign growths of bone that typically occur in the skull or jawbone. However, they can also present elsewhere, such as in the long bones of the body.

Osteomas may not cause any symptoms and do not always need treatment. When treatment is necessary, a doctor will likely recommend removing the growth. In other cases, they may monitor the growth over time and treat it only if needed.