From the Research
Chronic osteomyelitis and rheumatoid arthritis can be differentiated based on their distinct histologic features, with chronic osteomyelitis typically showing necrotic bone, neutrophil-rich inflammatory infiltrates, and reactive new bone formation, whereas rheumatoid arthritis demonstrates synovial hyperplasia, abundant plasma cells and lymphocytes, and invasive granulation tissue eroding articular cartilage and subchondral bone. The histologic features of chronic osteomyelitis include:
- Necrotic bone (sequestrum) with empty lacunae
- Neutrophil-rich inflammatory infiltrates forming abscesses
- Plasma cells and lymphocytes in the surrounding tissue
- Reactive new bone formation (involucrum)
- Bacterial colonies may be visible with special stains
- Fibrosis develops in long-standing cases 1 In contrast, rheumatoid arthritis is characterized by:
- Synovial hyperplasia with villous projections
- Abundant plasma cells and lymphocytes forming follicle-like structures
- Paucity of neutrophils except during acute flares
- Characteristic pannus formation shows invasive granulation tissue eroding articular cartilage and subchondral bone
- Fibrinoid necrosis may be present in vessel walls
- Rheumatoid nodules with central necrosis surrounded by palisading histiocytes may be found in periarticular tissues These histologic differences reflect their distinct pathophysiology, with chronic osteomyelitis being primarily an infectious process and rheumatoid arthritis being an autoimmune condition characterized by chronic synovial inflammation and progressive joint destruction through immune-mediated mechanisms 2. It is also worth noting that patients with chronic osteomyelitis may be at increased risk of developing rheumatoid arthritis, particularly those with more severe or recurrent osteomyelitis 3. However, the diagnosis of chronic osteomyelitis and rheumatoid arthritis should be based on a combination of clinical, radiological, and histopathological findings, rather than relying solely on histologic features 4.