Abstract
Pulmonary Langerhans cell histiocytosis which is histologically characterized by proliferation and infiltration of Langerhans cells is a rare entity. The patient was a 43-year-old man with a smoking history of 20 cigarettes/20 years. He presented to our hospital because miliary tuberculosis was suspected by bilateral diffuse reticular opacities on a chest x-ray at a medical checkup. A chest CT scan showed diffuse and granular structures, nodules with the diameter of less than 8mm and multiple cystic shadows in the bilateral lungs involving predominantly the upper lobes. Chest CT and MRI scans revealed a 35-mm osteolytic lesion in the right ilium. From these imaging findings, pulmonary Langerhans cell histiocytosis was suspected. However, no definite diagnosis was made even after trans-bronchial biopsy as well as bronchoalveolar lavage. So thoracoscopic biopsy of the right lung was performed. Histopathology revealed scattered nodules with various sizes ranging 3 - 5mm in diameter in the emphysematous lung as the background, eosinophilic infiltration and hyaline cicatrization surrounding the bronchiole and groups of sarcoidosis like epithelioid cells. Immunostaining revealed all cells to be S-100 protein positive. Langerhans cell histiocytosis was definitely diagnosed. Both pulmonary and bone lesions decreased in size 2 months after he stopped smoking.
