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. The disease is Osteochondroma (EFO_1000411).