Pulmonary Langerhans' cell histiocytosis: radiologic resolution following smoking cessation.

We describe two patients with histologically proven pulmonary Langerhans' cell histiocytosis in whom radiologic improvement occurred following smoking cessation. The patients had 23- and 25-pack-year smoking histories, respectively. High-resolution CT revealed multiple small nodules, located predominantly in the upper and middle lung fields. There was a close temporal relationship between smoking cessation and radiologic improvement.