Musculoskeletal and Skin Pathology for Medical II Students

Lab 1a Rheumatoid Synovitis (1Y000-44940)

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disease that typically affects multiple joints, especially the small joints in the hands and feet. The characteristic lesion is a diffuse, proliferative synovitis, which includes hyperplasia and hypertrophy of the synovial lining cells. These cells can give rise to a villous formation of the synovial surface. Also typical are an inflammatory infiltrate, predominantly of lymphocytes and plasma cells which may form lymphoid nodules, and an exudate of fibrin in the synovium and synovial space.

The subsynovial connective tissue may undergo reactive hyperplasia and is usually highly vascularized. When these changes are marked, the synovial lining is replaced by a mass of proliferated synovial cells, inflammatory cells, and blood vessels which can extend over the articular surface of the joint (a pannus) and can destroy the underlying cartilage. Chronic or intermittent synovitis can also severely  damage and weaken the joint capsules and tendons, and thereby contribute to the subluxation and ulnar deviation of the fingers seen in end stage rheumatoid arthritis.

Slides 1 - 2

Slide 1 Shows the fibrous capsule, the mononuclear inflammatory reaction, the villous proliferation of the synovium, and the brightly eosinophilic fibrin aggregates.
Slide 2 Shows fibrinoid material and synovial cell hyperplasia and hypertrophy on higher power. Although not well visualized in this projection slide, there is a predominantly mononuclear cellular infiltrate that is readily seen on histopathologic exam.

Digital Legends for Labs/Cases
Lab 1
1a | 1b | 1c | 1d | 1e | 1f | 1g
Gross & Radiographs
a | b | c | d | e | f | g | h 
Lab 2
2a | 2b | 2c | 2d | 2e | 2f

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Updated January 15, 2008