Acquired hyperostosis syndrome: spectrum of manifestations at the sternocostoclavicular region. Radiologic evaluation of 34 cases.

Thirty-four patients with chest wall hyperostosis, a condition which has been designated by various terms in the literature were evaluated radiologically. We prefer the name acquired hyperostosis syndrome (AHS), which we categorize into the complete, incomplete and possible form. In complete AHS, sternocostoclavicular hyperostosis is associated with axial and/or peripheral (endosteal, periosteal, enthesopathic, metaplastic) hyperostosis and with psoriasiform or acneform dermatosis. In addition, these three manifestations are accompanied by erosive or non-erosive peripheral and/or axial arthritis to a variable degree. Sometimes, concomitant findings which are consistent with ankylosing spondylitis are also to be found in the axial skeleton. AHS is manifested at 11 different sites on the anterior chest wall. Ossification forms of the costal cartilage, inflammatory enthesopathies (three different insertions) and focal hyperostoses as well as processes of remodelling of the ribs, clavicles and sternum which are described in detail have particular diagnostic significance. AHS can start simultaneously at one, two or several sites on the anterior chest wall. Conventional tomography (possibly supplemented by CT) is necessary for early diagnosis and for analysis of the various findings on the anterior chest wall.