Background: Unifocal Langerhans Cell Histiocytosis (LCH) is a rare idiopathic disease that is usually characterized by solitary bony lesions but can present as diffuse pulmonary infiltrates, most commonly due to cigarette smoking.
Case Report: We report the case of a 71-year-old female with a past medical history including pulmonary fibrosis, connective tissue disease, and childhood Tuberculosis, admitted initially with shortness of breath and non-productive cough. Radiological evaluation revealed bilateral pulmonary nodules, increasing in size, consistent with metastatic disease. The workup for TB and malignancy were negative. Transbronchial biopsy and washings were non-diagnostic. The patient then underwent thorascopic wedge biopsy of lung nodules and pleura. The pathology demonstrated Langerhans Cell Histiocytosis.
Conclusions: Unifocal LCH is a rare idiopathic disease with an unknown etiology and prognosis. Diagnosis can be successfully made by minimally invasive techniques. Thus, elderly patients with multiple lung nodules should not be assumed to have a disseminated cancer or infection and thorascopic biopsy represents a safe and efficient diagnostic technique.

Keywords: Histiocytosis, Langerhans-Cell, video-assisted thoracoscopic surgery, idiopathic pulmonary fibrosis