Iron in the synovial membrane in rheumatoid arthritis and other joint diseases.

Abstract

Histological examination of the synovial membrane demonstrated that iron deposits were a constant feature of the pathology of rheumatoid arthritis. Using material from 27 joints in 23 patients with classical or definite disease, Prussian blue positive staining was present in all but biopsy. Hemosiderin granules were seen in routine hematoxylin and eosin stained sections in 15 of the 27 biopsies. Iron was also present in the characteristic multinuclear giant cells which occurred in 1/3 of the biopsies. In 14 biopsies from non-rheumatoid joints, iron was absent except in 1 case of hemochromatosis and in 1 case of pigmented villo-nodular synovitis. Iron deposits in rheumatoid arthritis may arise from continued oozing of blood from the vascular granulation tissue into the synovial cavity. The possible significance of these findings in relation to the anemia and pathogenesis of rheumatoid arthritis is discussed.