[Idiopathic interstitial pneumonia (type B) with subacute progressively enlarged bullae]

A 70-year-old man with a 10-year history of seal engraving presented with exertional dyspnea and dry coughing. Chest roentgenograms showed an interstitial shadow and bilateral progressively enlarging bullae. Open lung biopsy led to the diagnosis of idiopathic interstitial pneumonia (Type B). The size of bullae usually does not change, so cases such as this are rare because the bullae continued to expand subacutely. Persistent stimulation by the inhaled A1 and Si may have played a role in the pathogenesis of this condition.