Codman triangle periosteal reaction
A Codman triangle is a type of periosteal reaction seen with aggressive bone lesions. The periosteum does not have time to ossify with shells of new bone (e.g. as seen in a single layer and multilayered periosteal reaction) in aggressive lesions, so only the edge of the raised periosteum will ossify.
The Codman triangle may be seen with the following aggressive lesions:
- osteosarcoma
- Ewing sarcoma
- osteomyelitis
- active aneurysmal bone cyst
- giant cell tumor
- metastasis
- chondrosarcoma (especially juxtacortical chondrosarcoma)
- malignant fibrous histiocytoma
History and etymology
It was first described by Ribbert in 1914 2. However, it is named after the American surgeon Ernest Amory Codman (1869-1940), who described it in the setting of Ewing sarcoma 3,4.