<prompt> A 40 year old woman has severe, disabling rheumatoid ahritis. Rheumatoid factor is positive. What would a biopsy of the synovium of her knee most likely reveal?A nearly normal synovium with scattered inflammatory cellsA non-proliferative synovitis with abscess formationA non-proliferative synovitis with many neutrophilsA proliferative synovitis with many lymphocytes, macrophages, and plasma cells  <response>: Severe rheumatoid ahritis causes a proliferative synovitis with extensive damage to the synovium of the joint. The synol membrane becomes markedly thickened pannus formation, with edematous villous projections that extend into the joint space. The intense inflammatory infiltrate that is present is typically composed of plasma cells, lymphocytes, and macrophages. Ref: Bednar M.S., Light T.R. 2006. Chapter 10. Hand Surgery. In H.B. Skinner Ed, CURRENT Diagnosis Treatment in Ohopedics, 4e. 