[Successful treatment of pleurodesis for seemingly intractable pleural effusion in pleural amyloidosis with rheumatoid arthritis].

We report a case of secondary amyloidosis with pleural involvement in a patient with rheumatoid arthritis. A 77-year-old man had received a diagnosis of rheumatoid arthritis 10 years previously. Bilateral pleural effusion of unknown etiology was noted 2 years prior to admission. A biopsy of the left pleura by video-assisted thoracic surgery did not reveal any evidence of the cause of his pleural effusion. The histological findings revealed chronic inflammation of the pleura on a hematoxylin-eosin (HE) stain, but treatment with an increased dose of corticosteroid did not improve his effusion. Right pneumothorax then developed. Based on the histological findings of a Congo red stain, the diagnosis was changed to pleural amyloidosis. An initial attempt at pleurodesis with OK-432 and a pleural patch with the patient's own blood was attempted but was not successful. Subsequently, pleurodesis with OK-432 and the patient's own blood improved his pleural effusion and pneumothorax. Pleural involvement in amyloidosis is extremely rare and is difficult to treat.