Diffuse idiopathic skeletal hyperostosis with fibrobullous change in upper lung lobes and dyspnea due to limitation of thoracic cage

A 48-year-old man was admitted to our hospital because of shortness of breath and abnormal shadows on chest roentgenograms. Although he had been given a diagnosis of ankylosing spondylitis (AS) at the onset of his symptoms, a diagnosis of diffuse idiopathic skeletal hyperostosis (DISH) was made by our orthopedics department on the basis of bone X-ray findings. Spirograms demonstrated a restrictive pattern and residual volume was increased. Total lung capacity and respiratory muscle function were normal, suggesting that the abnormal spirogram findings were due to decreased thoracic cage compliance. Chest roentgenograms and computed tomographic scans showed apical fibrobullous changes in both lungs, similar to those observed in AS. To our knowledge, this is the first case of DISH with pulmonary involvement to be reported to date. The pulmonary manifestations were similar to those of AS, and it was speculated that they were due to limitation of the thoracic cage.