Osteochondroma: Types, Causes, Symptoms, Diagnosis and Treatment

It is a benign (non-cancerous) tumor that develops during childhood or adolescence.

It is an abnormal growth that forms on the surface of a bone near the growth plate .

Growth plates are areas of cartilage tissue development near the ends of long bones in children.

Bone growth occurs around the growth plate, and when a child becomes an adult, the growth plates harden into solid bone.

An osteochondroma is an extension of the growth plate and is made up of bone and cartilage. As a child grows, an osteochondroma can grow as well.

Once a child reaches skeletal maturity, the osteochondroma usually stops growing as well.

In most cases of osteochondroma, no treatment is required other than regular monitoring of the tumor to identify any changes or complications.

Stedondroma is the most common benign bone tumor in children.

Because an osteochondroma often shows no symptoms, the tumor can only be discovered when a child notices a bump or reports pain. For some children, osteochondroma can never be discovered.

An osteochondroma looks like a bony projection on the outer surface of a bone, like a bony fungus on a stem, usually near a growth plate area.

It can occur in any bone, but is most often seen around the knee or upper arm.

Most osteochondromas are diagnosed in patients under the age of 20 and are more likely to affect boys than girls

Osteochondromas can develop as a single tumor (osteocartilaginous exostoses) or as many tumors (multiple osteochondromatosis).

Because symptoms and treatment options can vary depending on the form a patient has.

Solitary osteochondroma

Solitary osteochondromas are believed to be the most common benign bone tumors, accounting for 35% to 40% of all benign bone tumors.

Cancer usually comes from a malignant tumor, not a benign one, and does not metastasize to other organs in the body.

As the child grows, a solitary osteochondroma may develop if the bone grows from the growth plate instead of aligning with it.

Solitary osteochondromas are commonly found at the end of long bones where they meet to form joints, such as the knee, hip, and shoulder. This bone growth may have a stem that protrudes from the normal bone.

If the tumor has a stalk, the structure is called pedunculated. If the tumor extension is attached to the bone with a wider base, it is called sessile.


The exact cause of osteochondroma is unknown. It is not the result of injury. Both men and women are equally likely to develop it.

Osteochondromas are believed to be associated with a gene called EXT 1.

At present, it is not well understood how a defect in this gene can cause tumors. Researchers are still conducting studies to find out.

Because the cause of solitary osteochondroma is unknown, doctors have not been able to find a way to prevent it.

There is a theory that this tumor may be the result of genetic abnormalities.


In many cases, solitary osteochondromas do not cause any symptoms, or symptoms can appear long after the tumors develop.

Osteochondroma is most often diagnosed in patients between the ages of 10 and 30.

Symptoms of an osteochondroma can include:

  • A painless bump near the joints – the knee and shoulder are most often involved.
  • A visible lump under the skin.
  • Deformity.
  • Growth disturbances.
  • Nerve compression: causing muscle weakness.
  • Pain with activity: An osteochondroma can be located under a tendon (the hard, fibrous tissue that connects muscle to bone). When it is, the tendon can move and “click” on the bone tumor, causing pain.
  • Numbness or tingling: An osteochondroma can be located near a nerve, such as behind the knee. If the tumor presses on a nerve, there may be numbness and tingling in the associated limb.
  • Changes in blood flow: A tumor pressing on a blood vessel can cause periodic changes in blood flow. This can cause loss of pulse or changes in limb color. Changes in blood flow as a result of an osteochondroma are rare.

In some cases, an injury can cause the stem of a pedunculated osteochondroma to break. This will cause immediate pain and swelling in the tumor area.


Medical exam

Because many osteochondromas do not cause any discomfort or other symptoms, they are often discovered by accident when an X-ray is done for an unrelated reason.

If you have symptoms that prompt you to seek medical attention, your appointment will begin with a medical history and physical exam.

Medical history and physical exam

Before a physical exam, your doctor will talk with you about your general health, as well as your symptoms, to get a good history of the problem.

During the physical exam, your doctor will look for tenderness over the bone and monitor your range of motion in the area of ​​your pain.


To diagnose osteochondroma, your doctor will order imaging tests:

  • X-rays: These tests create clear images of dense structures such as bone and will show the bone growth of an osteochondroma.
  • Other imaging scans: Doctors may also order computed tomography (CT) scans or magnetic resonance imaging (MRI) to help better define the tumor. These scans can provide more detail, especially of the soft tissues.

An MRI can be used to look for cartilage on the surface of the tumor. Although it is rare for an osteochondroma to develop into a cancerous tumor, it is possible.

In adults, a thick covering of cartilage over the tumor is a sign of this change.

A tumor in an adult patient should be examined for cancer if it is enlarging or has become painful.


A biopsy is necessary to detect cancer. In a biopsy, a sample of tissue is taken from the tumor and examined under a microscope.

Your doctor may give you a local anesthetic to numb the area and take a sample with a needle. Biopsies can also be done as a small operation.


Non-surgical treatment

In most cases of osteochondroma, treatment consists of careful observation over time.

Your doctor may want to do X-rays regularly to monitor any changes in the tumor.

Surgical treatment

Your doctor may consider surgery if your osteochondroma:

  • Causes pain.
  • It puts pressure on a nerve or blood vessel.
  • It has a large cartilage plug.

To completely remove an osteochondroma, your doctor will perform a surgical procedure called an excision. In this procedure, the tumor will be removed to the level of normal bone.

The time it takes to return to daily activities will vary depending on the size and location of the tumor. If you have any pain or discomfort, you can limit some activity.

Your doctor will provide you with specific instructions to guide your recovery.

Multiple osteochondromatosis

Multiple osteochondromatosis is also called multiple osteocartilaginous exostoses, multiple hereditary exostoses (MHE), familial osteochondromatosis, multiple hereditary osteochondromatosis, or diaphyseal aclasia.

The number and location of osteochondromas varies. Pedunculated and sessile tumors can develop.

In more severe cases, multiple osteochondromatosis can cause the bones to grow abnormally. For example, many patients have short stature, twisted knees and ankles, and deformities of the forearms.

Because of these more obvious signs, children with severe multiple osteochondromatosis are often identified early.

However, like solitary osteochondroma, mild osteochondromatosis may not be diagnosed until early adulthood. Multiple osteochondromatosis is more common in men than women.

The risk of these benign tumors changing to cancer (malignant transformation) is greater than solitary osteochondroma.


About 70% of the time, multiple osteochondromatosis is inherited, and the other 30% occurs randomly.

Like solitary osteochondroma, alterations in genes called EXT genes are believed to be the cause of this disease, and research is ongoing.


The symptoms of multiple osteochondromatosis are similar to those of solitary osteochondroma, only they are often more severe. It can cause painless bumps at tumor sites.

Pain and other discomfort are possible if the tumors put pressure on soft tissues, nerves, or blood vessels.


The diagnosis of multiple osteochondromatosis includes a medical history and physical exam, as well as imaging tests.

Multiple osteochondromatosis can be seen on a plain X-ray. The findings are generally more severe than those of solitary osteochondroma.

X-rays and CT scans

An X-ray is a diagnostic test that uses invisible beams of electromagnetic energy to produce images of internal organs, bones, and tissues onto film.

Standard X-rays are done for many reasons, including the diagnosis of bone tumors or lesions.

X-rays pass through structures in the body onto specially treated plates (similar to camera film) and a ‘negative’ type image is produced (the more solid a structure, the whiter it appears on the film).

Computed tomography (CT or CT) is also used to diagnose this condition, it is a non-invasive imaging procedure that uses a combination of special X-ray equipment and sophisticated computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, from the body.

These cross-sectional images of the area being studied can then be examined on a computer monitor or printed.

General X-rays are not as detailed as CT scans, which show images of any part of the body.

X-rays do not show as much detail as CT scans of bones, blood vessels, soft tissues, and internal organs that provide greater visual clarity. CT scans also minimize radiation exposure.

For a better visualization in the scans, a special dye can be injected or ingested that will help the organs and tissues to stand out more easily.

In regular X-rays, beams of light are directed towards the part of the body where the organ to be studied is located.

After the energy beam passes through the skin, muscles, organs, bones, etc., a plate behind the body captures these energy beams.

Although a lot of information can be obtained with a standard x-ray, many details about the organs and other structures of the body are not reflected.

In CT scans, the energy beam that is expelled from the x-rays moves in a circular fashion around the body, allowing a better view of an organ or tissue.

In both CT scans and X-rays, the information derived from these tests is sent to a computer that interprets the data sent by the X-rays and displays it as an image on a screen.

Radiologists can easily diagnose cancer, infectious and cardiovascular diseases, musculoskeletal disorders, and trauma with the help of specialized equipment and expertise in creating and interpreting CT-derived images.

Chest CT scans can also be used to visualize needle placement during biopsies of chest organs or tumors, or during aspiration (removal) of fluid from the chest.

This is helpful in managing tumors and other chest conditions before and after treatment. CT scans can be done with or without “contrast.”

Contrast refers to a substance taken by mouth or injected into an intravenous line that makes the particular organ or tissue under study show up more clearly.

Fasting may be required for certain contrast tests, your doctor will notify you if this procedure is necessary before performing the test.

There are certain tissues in the body that allow the passage of most X-rays such as blood, skin, fat and muscle, which then appear dark gray in the image emitted by the screen.

Tumors and bones, being denser than soft tissues, allow only some of the X-rays to pass through, which is why they are reflected in white in the image.

When there is a cut in a bone, the x-ray beam passes through the cut space and is reflected as a black line on the white bone.

Options are available for bone and soft tissue tumors, and some children will need a combination of these therapies.


Treatment for this condition will depend on your doctor, who will take into account the following:

  • Scope of the disease.
  • Your tolerance for specific therapies, medications, and procedures
  • Your age, general health, and medical history.
  • Expectation for the course of the disease.
  • Your preference or opinion.

Treatment for osteochondromas varies significantly depending on the size of the overgrowth and the individual’s symptoms. Treatment generally includes:

  • Medicines: to improve pain.
  • Surgery: to remove the cancerous mass.

In most cases of osteochondroma, once the diagnosis has been made by your child’s doctor, no further action is necessary.

These tumors will stop growing and remain stable when your child’s bones stop growing.

Surgical treatment

If your child’s osteochondroma is causing pain, restricting movement of a joint, or affecting growth, surgical removal may be indicated.

Treatment for osteochondroma is generally a simple surgical removal of the lesion from the surface of the bone.

The surgeon will be careful not to damage your child’s growth plate to ensure normal physical development after the operation.

If you have any symptoms of a tumor becoming cancerous, you should be evaluated by a doctor who specializes in treating bone tumors (an orthopedic oncologist).

When an osteochondroma becomes cancerous, it most commonly develops into a cancer called chondrosarcoma.

If surgical removal of an osteochondroma is indicated, the procedure is the same as for a solitary tumor.

Deformities such as twisted knees or ankles may require surgery to straighten the bone.

If multiple chondromatosis becomes cancerous, treatment will depend on the stage of the cancer’s progress.

In general, malignant tumors are removed by surgery. Radiation therapy and chemotherapy are often used in combination with surgery.

Non-surgical treatment

In most cases, treatment consists of careful observation over time.

Your doctor may want to do X-rays regularly to monitor any changes in the tumors.

The indications for surgical removal of tumors are the same as for solitary osteochondromas: pain, pressure on nerves or blood vessels, and a large layer of cartilage.