Figure 2

Histopathological features of synovium in patients with early (E) or long-standing (L) rheumatoid arthritis. (E-02) The proliferation of synovial lining cells resulted in fewer than four layers. There is diffuse infiltration of macrophages in the sublining regions. (E-07) The proliferative lining layer shows a typical palisading structure of the intimal lining layer. (E-12) The specimen shows proliferation of synovial lining cells, in places to more than five layers, associated with a typical palisading structure and several non-foreign-body-type giant cells. The lesions manifest underlying proliferation of blood vessels at the arteriole level, associated with many cell infiltrates composed of lymphocytes and plasma cells in the sublining regions. There are foci of lymphocyte aggregates, close to postcapillary venules, resembling lymphoid follicles, but lacking germinal centers. (L-01) In contrast to E-12, there are lymphoid follicles with germinal centers.