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.

See also

• periosteal reaction