Osteochondroma, Causes and Symptoms

Osteochondroma is a benign tumor that grows slowly and usually begins near the ends of long bones. It may be identified at any age, though it universally develops during childhood as the bone grows.  Once the child stops growing, the osteochondroma is also stops growing, but remains in place. Because this tumor is benign, it usually does not pose a significant risk or concern, and can usually be left untreated.  It is a disease that is thought to affect approximately 1-2% of the human population, though many are undiagnosed, meaning that the true prevalence may be even greater.

The most common time for diagnosis of an osteochondroma is in children who have had, or who are going through, large growth spurts. For unknown reasons, it is usually more prominent in males. Females who have this disease tend to contract it slightly earlier, due to earlier adolescence. This tumor consists of a stalk of bone growing away from the nearby growth plate, and is covered by a thin cap of cartilage. On occasion, the osteochondroma can become painful, may fracture, or may press upon nerves or tendons.  Rarely, an osteochondroma may transform into a malignancy such as chondrosarcoma, which generally manifests as growth or discomfort after reaching adulthood.

Anatomy of the Bone

The bone is a complex part of the human body. It consists of the following:

  • The articular cartilage – The hard cartilage at the head of the bone
  • Periosteum – The covering of the compact and cortex of the compact bone
  • Cancellous tissue – The spongy part of the bone

Bones do more than simply shape the body and act to help stabilize it during motion. At the ends of bone are growth plates, known as physes.  The majority of the growth in bone length comes from these physes.  The formation of an osteochondroma Is thought to result from an abnormality associated with the physis development during growth.

Types of Osteochondroma

Osteochodroma can be divided into two main categories:

  • Solitary osteochondroma – This is the most common form of this type of tumor and forms on only one bone in the body. These osteochondromas may account for up to 35-40% of all benign bone tumors.
  • Multiple osteochondromas – This is when a child has more than one occurrence of osteochondroma. The vast majority of the time, multiple occurrences are inherited in a condition called Multiple Hereditary Osteochondromas (or Multiple Hereditary Exostoses); only 30% of the time do they appear randomly. Patients with this condition often have alterations in the growth of their long bones, and have an increased risk of developing a chondrosarcoma in one of the tumors.

Causes of Osteochondroma

There are many causes of osteochondroma. While nearly all cases occur in children, there are a variety of reasons why these tumors form:

  • Inherited from a family member – Often seen with multiple osteochondromas, in a condition known as Multiple Hereditary Osteochondromas (or Multiple Hereditary Exostoses).  These frequently are identified during earlier during childhood.
  • Age – Osteochondromas always develop during childhood or adeloscence, though they may not be noticed until adulthood.  Any continued growth of the tumor into adulthood should warrant a detailed investigation.
  • Previous radiation – If a child has been treated using radiation, they are at a slightly increased risk of developing a tumor. The reason for this is not entirely understood.

Symptoms of Osteochondroma

Usually, the symptoms of osteochondroma are fairly minor, and in many cases the child does not experience any at all. However, because of the small risk of an osteochondroma turning malignant, it is always a good idea to visit a physician for examination.  

The following are common osteochondroma symptoms. Keep in mind that everyone’s body is different and may experience only some or none of these:

  • A painless bump near a joint
  • Snapping sensation of overlying tendons
  • Fracture of an osteochondroma
  • Pain if the tumor is pressing on a nerve ending

Osteochondroma symptoms are typically only felt if the tumor is pressing against another structure, such as a nerve or a tendon. Otherwise, the biggest sign is a small painless mass. In any case, it is always important to see a doctor to ensure the tumor is benign.  

The multidisciplinary team of orthopaedic experts at North Shore-LIJ Orthopaedic Institute's Trauma Services in New York treats osteochondroma as well as a broad range of conditions that affect the bones within the body.

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