A 73-year-old woman was diagnosed with interstitial pneumonia in 2006; however, the disease was not progressive. Four years later, purpura, peripheral neuropathy, and increased levels of myeloperoxidase antineutrophil cytoplasmic antibodies (583 EU/mL) and C-reactive protein (2.27 mg/dL) were observed, and a diagnosis of microscopic polyangiitis was made. Treatment with prednisolone and azathioprine was initiated. However, on the 35th hospital day, chest computed tomography showed

more »

... num and subcutaneous emphysema without aggravation of the interstitial pneumonia. To our knowledge, this is the first report of pneumomediastinum as a complication of microscopic polyangiitis associated with interstitial pneumonia.