A 49 year-old Caucasian male, smoker (15 pack-year), had at the beginning of his disease an additive, symmetric polyarthritis, affecting predominantly the small joints of the hands, wrists, shoulders and tibiotarsal joints. The autoimmune study revealed ANA and anti-ribosomal P protein antibodies positivity. An undifferentiated connective tissue disease was diagnosed and treatment with deflazacort, naproxen and hydroxychloroquine was begun. Two years later, he starts exertional dyspnea, without other respiratory symptoms. A chest high-resolution computerized tomography scan was performed, evidencing diffuse "ground-glass" opacities. Respiratory functional study showed low diffusion capacity. The bronchoalveolar lavage (BAL) revealed a neutrophilic and eosinophilic (20%) alveolitis, which was not associated with peripheral blood eosinophilia. The definitive diagnosis was obtained by a surgical lung biopsy, which showed features consistent with Descamative Interstitial Pneumonia (DIP). This rare entity is referred as a smoke-related disease. The debate about an eventual association of DIP with autoimmune diseases and BAL eosinophilia is discussed by the authors based on the present clinical case features.