Osteochondroma is a common, non-cancerous bone tumor that often originates from the growth plates in children and adolescents. This abnormal growth forms on the bone surface, near where bones lengthen. While typically developing during younger years, these growths can persist into adulthood or become noticeable later in life. Osteochondromas are generally considered benign.
What Is Osteochondroma?
Osteochondroma is characterized as an overgrowth of cartilage and bone, appearing as a projection on the surface of a bone. These tumors commonly develop near the ends of long bones, such as around the knee, hip, or shoulder, where growth plates are active. They are essentially outgrowths of the growth plate itself, composed of both bone and a cartilage cap.
The development of an osteochondroma forms a stalk-like structure or a broad-based growth. While osteochondromas are benign and do not spread to other parts of the body, there is a very small possibility of malignant transformation.
Symptoms in Adults
In adults, osteochondromas can become symptomatic due to the cessation of skeletal growth. The presence of the tumor can lead to irritation of surrounding tissues, nerve compression, or the formation of fluid-filled sacs called bursae. A common symptom is pain, which may arise from a tendon snapping over the bony outgrowth during movement or from direct pressure on adjacent nerves or blood vessels.
Adults might also notice a palpable, firm mass near a joint, most frequently around the knee or shoulder. This mass can sometimes restrict the normal range of motion in the affected joint. In some instances, the stalk of the osteochondroma can fracture, causing a sudden onset of sharp pain.
Diagnosis and Treatment Options
The diagnosis of an osteochondroma begins with a physical examination, where a doctor may feel a firm, immobile mass. Imaging studies are then used to confirm the diagnosis and assess the tumor’s characteristics. X-rays are the first step, revealing a bony outgrowth from the bone surface.
Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) scans provide more detailed images, helping to evaluate the cartilage cap thickness and its relationship to surrounding structures like nerves and blood vessels. These advanced imaging techniques are particularly useful in adults to monitor for any changes in the tumor. For asymptomatic or mildly symptomatic osteochondromas, conservative management involving careful observation and pain relief is recommended.
If the osteochondroma causes significant pain, limits joint movement, or leads to complications like nerve compression, surgical removal may be advised. The surgical procedure, known as excision, involves removing the bony outgrowth and its cartilage cap. Recovery time can vary, but patients undergo a period of rehabilitation to restore strength and range of motion in the affected limb.
Outlook and Rare Complications
The long-term outlook for adults with osteochondroma is excellent following management. Most individuals experience a full recovery with resolution of their symptoms. However, it is important to be aware of rare potential complications.
A rare but serious complication is malignant transformation into chondrosarcoma, a type of cancerous tumor. This occurs in approximately 1% of solitary osteochondroma cases and up to 5-25% in cases of multiple osteochondromas. Signs that may indicate malignant transformation include rapid growth of the tumor in adulthood, increasing pain, or a cartilage cap thicker than 2-3 cm on imaging.
Other rare complications can include compression of nearby nerves or blood vessels, leading to symptoms like numbness, tingling, or changes in circulation. Bursa formation around the tumor can also occur, causing localized inflammation and pain. Regular follow-up care, including evaluations and imaging, is important for monitoring any changes in the osteochondroma to ensure early detection and management of any potential complications.