What's your diagnosis? It has some kind of immunological cause. It's not sarcoidosis. I'll post the correct answer in three days!
Correct answer: Caplan's syndrome. This is multiple, bilateral lung nodules (0,5 - 5 cm) in coal workers with rheumatoid arthritis, caused by an inflammatory reaction to external allergen. There's an increased risk of nodule formation in exposure to silica, asbestos and anthracite.