Pulmonary histiocytosis X.

g twice a day.In November 1994 she was re-admitted to a secondhospital with a right-sided pneumothorax. In addition tothe pneumothorax, the chest x-ray showed diffuseinterstitial infiltration of both lungs, with normal lungvolumes. Computed tomography (CT) of the chest showeddiffuse interstitial disease, with multiple thin and thick-walled cysts of variable size and multiple nodular changesinvolving the upper two-thirds of both lungs. Thepneumothorax resolved a few days after treatment withclosed chest tube. The patient was discharged homewithout a definite diagnosis of her pulmonary disease.The patient developed progressive shortness of breathover the subsequent three years. In May 1997, she washospitalized in our institution with acute left-sided chestpain and increasing shortness of breath for 24 hours. Chestx-ray and CT scan of the chest revealed a left-sidedpneumothorax; there was also progression of theinterstitial and cystic changes in her lungs and there was