Forty-five-year-old man with small nodular and ground-glass opacities on CT

We present the case of a 45-year-old man who reported 2 years of cough and expectoration and 1 year of dyspnoea. He had a history of dry nasal snuff inhalation 15 times/day for 10 years, worked as a herdsman with an unremarkable medical history and lived in a high-altitude region (altitude, 4700 m). His oxygen saturation was 86% on room air (altitude, 3650 m). The laboratory results were normal except those for polycythaemia (haemoglobin, 209 g/L) and hyperglobulinaemia (immunoglobulin G, 20.71 g/L), the antinuclear antibody (ANA) was 1:100, and lymphocytes and calcium levels were normal. Spirometry results were within normal limits with forced expiratory volume in one second (FEV1) of 82%, forced vital capacity (FVC) of 84%, total lung capacity (TLC) of 80% and diffusion capacity of the lung for carbon monoxide (DLCO) of 93% predicted values. His chest CT revealed small solid nodules in the upper lobes, diffuse bilateral ground-glass opacities (GGOs) …