Caplan’s syndrome [Anthony Caplan, English physician, 1907–1976] , a condition of pneumoconiosis with symptoms of rheumatoid arthritis and radiographic evidence of intrapulmonary nodules. It is caused by inhalation of coal dust and results in inflammation and scarring of the lungs. Although there is no treatment for Caplan’s syndrome, it is important to treat the rheumatoid arthritis. Also called rheumatoid pneumoconiosis.