Coexistence of Diffuse Idiopathic Skeletal Hyperostosis and Late-Onset Ankylosing Spondylitis in a Sixty-year-old Patient

Diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) are two diseases characterized by ossification of the ligaments and tendons in both the axial skeleton and peripheral sites with very different pathologies. Coexistence of DISH and AS is a rare condition and there are relatively few cases in the English-language literature. In this paper, we report a human leukocyte antigen-B27-negative patient who presented with the typical appearance of DISH on the dorsal radiograph and also had sacroileitis, suggesting AS. We discussed prognosis of the late-onset case and the interaction of two diseases in this coexistence