Which histopathologic feature is seen in rheumatoid arthritis and contributes to fibrosis and scar formation?

• A. Pannus formation
• B. Osteophyte formation
• C. Eburnation
• D. Gouty tophi

Answer: (A)

Chronic synovitis in rheumatoid arthritis drives pannus formation—a proliferative, inflammatory granulation tissue that arises from the synovium and grows over the articular cartilage. This pannus is rich in inflammatory cells and fibroblasts with new blood vessels, and it actively invades cartilage and subchondral bone. As the inflammatory process becomes chronic, the pannus undergoes fibrous organization, leading to fibrosis and scar formation within the joint. This fibrotic tissue contributes to joint stiffness and destructive remodeling seen in RA. In contrast, osteophyte formation and eburnation point to osteoarthritis, and gouty tophi reflect urate crystal deposition, not the pannus-driven fibrosis characteristic of RA.