[Pulmonary histiocytosis, then bronchiolo-alveolar cancer in HIV-1 infection].

Introduction: Langerhans cell pulmonary histiocytosis is a rare disease, primarily enhanced by smoking, and of unclear mechanism.
Observation: A 42 year-old man, smoking 25 packs-years, was infected by a type 1 human immunodeficiency virus (HIV-1). He successively developed pulmonary emphysema, Langerhans cell pulmonary histiocytosis and alveolar bronchial carcinoma of the lower right pulmonary lobe, which was fatal.
Discussion: We discuss the concomitance of pulmonary histiocytosis and alveolar bronchial carcinoma, exceptional in the literature, and the eventual enhancing role of HIV-1 infection. The principal incriminating factor in pulmonary histiocytosis probably remains smoking, but the HIV-1 infection may have participated in the emergence of the neoplastic pathology.