Osteochondroma (OC) is a developmental anomaly consisting of bony protuberance covered with a cartilage cap of various thicknesses, which emanates outwardly from the surface of bone being continuous with medullary cavity of the underlying bone. Actually, OC has been considered as a hamartomatous or developmental anomaly in the distinct clinical settings of either solitary form or multiple hereditary forms (osteochondromatosis). However, germline mutations in EXT1 and EXT2 genes have been found in the development of solitary and multiple forms of the disease [1–3], and thus, OC should be considered a unique form of a benign bone tumor rather than a hamartoma. Most patients (86%) present to have a solitary lesion [4]. Exostosis is a benign protuberance with a cartilage cap extending outward from an underlying bone, including two forms of OC and degenerative marginal osteophyte [5].