Osteochondroma

Osteochondroma is a cartilage-capped bony projection that grows from the surface of a bone. It often develops during childhood or adolescence, while the skeleton is still growing. Most osteochondromas are benign, meaning they are not cancer. Growth usually stops when the skeleton matures, although symptoms can occur if the projection presses on nearby tissues.

Many osteochondromas cause no symptoms and are discovered by chance on an imaging test performed for another reason. When a growth is near a joint, nerve, blood vessel, or tendon, it may cause a noticeable lump or local symptoms. An osteochondroma near the knee, for example, may be felt around the lower thigh or upper shin.

An osteochondroma forms when cartilage near a bone’s growth plate grows outward and then develops into bone. This creates a projection that is continuous with the underlying bone and is often covered by a layer of cartilage. The process usually begins during the years when bones are lengthening.

Solitary and inherited osteochondromas

Most solitary osteochondromas are sporadic, meaning they occur without a known inherited cause. Hereditary multiple osteochondromas result from an inherited gene change and can cause many growths in one person or family. This inherited form is also called hereditary multiple exostoses.

Osteochondroma is not generally caused by diet, exercise, or an injury. A person without known risk factors can still develop a solitary growth, so the absence of a family history does not rule it out. Family history and inherited gene changes are nonmodifiable factors, while age-related risk is linked to the period of skeletal growth.

Diagnosis begins with a medical history and physical examination, followed by imaging of the affected area. The clinician may ask when the lump or symptoms began, whether they are changing, and whether relatives have had multiple osteochondromas.

What osteochondroma radiology can show

An X-ray can show the characteristic bony projection and its continuity with the underlying bone. MRI can assess the cartilage cap, nerves, blood vessels, and other soft tissues, while CT can clarify complex anatomy. A biopsy is usually considered only when imaging is atypical or malignant change is suspected. People with multiple growths or a family history may be referred for genetic counseling or testing, and a clinician may examine other bones for additional osteochondromas.

Osteochondroma treatment depends on symptoms, growth pattern, location, skeletal maturity, and whether imaging suggests a complication. Many growths can be monitored, while symptomatic or concerning growths may be removed surgically.

Active monitoring

Observation is often appropriate when an osteochondroma is not causing problems. A clinician may recommend periodic review and imaging to monitor pain, enlargement, pressure effects, or changes after skeletal maturity. Many asymptomatic growths do not need immediate treatment, but new symptoms should be reported.

Surgical removal

An orthopedic surgeon may recommend excision for persistent pain, restricted movement, pressure on a nerve or blood vessel, deformity, fracture risk, or suspicious change. Recovery depends on the growth’s location and the extent of surgery. The removed tissue may be examined by a pathologist to confirm the diagnosis and check for concerning changes.

Most solitary osteochondromas have an excellent outlook. They usually stop enlarging after skeletal maturity and do not affect life expectancy. Many remain harmless throughout life, although a growth can still cause local pressure or irritation depending on its location.

Hereditary multiple osteochondromas may require ongoing orthopedic follow-up because new growths, skeletal differences, or pressure-related symptoms can develop during growth. Recurrence after complete removal is uncommon but possible if some of the growth remains. Overall, the outlook is often favorable, but monitoring is important when multiple osteochondromas are present.

Arrange an evaluation for a new hard lump near a bone or joint, persistent pain, reduced movement, or symptoms such as numbness, tingling, or changes in limb shape or length. These findings do not always indicate a serious problem, but they need assessment to identify the cause.