Coexistence of diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis.

To the best of our knowledge, only two patients with concurrent diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) have been reported so far. Here we present 3 patients in whom clinical and radiological findings indicative of DISH and AS coexisted. Two of these cases exhibited HLA B27. Although the presence of sacroiliitis would appear to exclude DISH, calcification and ossification of the anterior common vertebral ligament (ACVL) confirmed diagnosis of the latter disease.