Solitary osteochondroma is a developmental abnormality of bone. It occurs when part of the growth plate forms an outgrowth on the surface of the bone. This bone outgrowth may or may not have a stalk. When a stalk is present, the structure is called pedunculated. When no stalk is present, it is called sessile.
An osteochondroma may grow in a child or adolescent. Its growth usually stops at maturity.
Solitary osteochondromas are thought to be the most common noncancerous (benign) bone tumor. They account for 35 percent to 40 percent of all benign bone tumors.
Solitary osteochondroma is diagnosed in patients aged 10 to 30. It occurs equally in males and females. It does not result from injury. It is thought to arise during skeletal growth when bone grows away from the growth plate instead of in line with it. Because the cause of solitary osteochondroma is unknown, doctors have not been able to find a way to prevent it.
A plain X-ray will show the bony growth. A magnetic resonance imaging (MRI) scan may be used to look for cartilage on the surface of the bony growth. Such cartilage in an adult patient should be checked for cancer if it is larger than two centimeters in size, or if there is pain.