MSH: A cartilage-capped benign tumor that often appears as a stalk on the surface of bone. It is probably a developmental malformation rather than a true neoplasm and is usually found in the metaphysis of the distal femur, proximal tibia, or proximal humerus. Osteochondroma is the most common of benign bone tumors.,NCI: A benign cartiliginous neoplasm arising from the metaphysis of bone.,NCI: A common, benign cartiliginous neoplasm arising from the metaphysis of bone. The tumor grows on the surface of the bone; it may be pedunculated or sessile. It is characterized by the presence of chondrocytes, a cartilage cap, and a fibrous perichondrium that extends to the periosteum of the bone. In some cases, there is deletion of 8q24.1 chromosome locus.