Certain unusual radiological appearances in the chest of coal-miners suffering from rheumatoid arthritis.

Caplan's syndrome, originally identified in coal miners with progressive massive fibrosis. It is a combination of rheumatoid arthritis (RA) and pneumoconiosis that manifests as intrapulmonary nodules, which appear homogenous and well-defined on chest X-ray. Digital facsimile from Thorax.bmj.com at this link.