Osteochondroma is the most common benign tumor or tumorlike lesion of bone. The radiographic appearance of this tumor is often diagnostic and reflects its pathologic characteristics, that is, a lesion composed of cortical and medullary bone with an overlying hyaline cartilage cap. However, it is the continuity of this lesion with the underlying native bone cortex and medullary canal that is pathognomonic of osteochondroma.