Abnormal metaphysis morphology Metaphyseal enchondromatosis HP:0005868 UMLS:C4025121 An enchondroma is a benign growth of cartilage that develops within the medullary cavity of bone. Enchondromatosis refers to the presence of multiple enchondromas, and this term refers to the presence of multiple enchondromas within the medulla of metaphyseal bone. Radiographically an enchondroma presents a an oval, linear, or pyramidal osteolytic (radiolucent) lesion with well defined margins.