[Long-term follow up study of four cases of pulmonary Langerhans' cell histiocytosis].

: We reported the clinical features of 4 cases with pulmonary Langerhans' cell histiocytosis. All of them were men who had a history of smoking. They ranged in age from 23 to 46 years. Cases 1 and 3 did not stop smoking, while Cases 2 and 4 did stop smoking. All of the chest CTs revealed small nodules and cysts, and during the follow-up period of 8 to 13 years, the numbers of nodules decreased and the walls of the cysts became thin in all of the cases. Their pulmonary function tests revealed restrictive impairment in 3 cases and reduced diffusion capacity in 2 cases, but none showed obstructive impairment. FEV1% and DL(CO) deteriorated during the follow-up period. Case 1 died of respiratory failure after 8 years. Cases 2 and 4 were both alive with home oxygen therapy after 11 and 12 years, respectively. Case 3 was alive but complained of dyspnea on exertion after 13 years. In conclusion, all of the 4 cases showed deterioration of pulmonary function, and one of them died due to respiratory failure. The prognosis of patients with pulmonary Langerhans' cell histiocytosis appears to be poor.