Forestier's disease, ankylosing hyperostosis of the spine, or diffuse idiopathic skeletal hyperostosis (DISH), is a relatively common disorder affecting middle aged and elderly individuals (1–11). It is characterized by a distinctive type of spinal ossification. Extraspinal heterotropic ossifications at sites of ligamentous and tendinous attachments are not uncommon (2,4,7,9–11). Although frequently asymptomatic, many patients complain of spinal stiffness and backache (2,4,9,11). Pathologic and radiologic studies have shown that the abnormal ossification process is a slowly progressive one, which may take several years for its completion (2,5,8,11).
We report here a 77‐year‐old man who developed progressive backache which was initially thought to result from advanced diffuse idiopathic skeletal hyperostosis. Serial radiographs, however, showed progressive disappearance of the distinctive lumbar hyperostosis. He was later discovered to have a leaking abdominal aortic aneurysm.