Histology of RA

Histology:

The characteristic that is the most common result of rheumatoid arthritis is the erosion/destruction of joints. This result happens due to the increase in number of immune cells in the synovial membrane.
Below are images that illustrate what rheumatoid arthritis looks like at a histological level.

Figure 1:  Rheumatoid Arthritis in the knee joint.

Figure 1: (A) shows the knee joint being exposed in order to show the erosion of the articulate cartilage of the femur. (B) shows the pannus (tissue) growing over and destroying the cartilage. (C) shows the synovium  portraying finger- like projections due to the presence of the inflammatory cells. 



Figure 1: The synovial lining in patients without proliferation of the lining vs. those with proliferation of the lining due to rheumatoid arthritis.

Figure 1: represents the synovial lining comparing between normal lining and the proliferation of the lining due to rheumatoid arthritis. E stands for patients with early rheumatoid arthritis while L stands for long-standing rheumatoid arthritis. In E-02 the "proliferation resulted in less than four layers and a diffuse infiltration of macrophages in the sub lining regions" (Tsubaki). E-07 shows a typical palisading structure of the intimal lining layer in the lining that was proliferated. E-12 shows "proliferation of the synovial lining more than five layers.  It has a typical palisading structure with several non-foreign body type giant cells" (Tsubaki). There are lesions that make the proliferation of the blood vessels visible at the arteriole level. "This is associated with cell infiltrates composed of lymphocytes and plasma cells in the sub lining regions." (Tsubaki)  There are foci resembling lymphoid follicles however, they lack germinal centers. If comparing E-12 with L-01, L-01 does have lymphoid follicles with germinal centers.

 

 

 

 

 

Figure 3: Villous Hypertrophy of the Synovium



Figure 3: shows the increase in the volume of the synovium due to the enlargement of its component cells which causes the synovium to have a fingerlike appearance.




Figure 4: Chronic inflammation

Figure 4: shows chronic inflammation of the synovium which means that the number of cells has increased.

 

 

Figure 5: Synovial Villi eroding cartilage at the joint.

 

Figure 5: Shows how synovial villi can grow and eventually grow over the joint.

 

 

 

 

 

 



Figure 6: Infiltration of chronic inflammatory cells (in the wrist).



Figure 6: Macrophages, lymphocytes, and plasma cells moving into synovial villi from tissue in the wrist.



Figure 7: Increase in the number of synoviocytes.

Figure 7: Shows the increase in the number of the specialized cells in the synovium called synoviocytes. Together with other immune cells, such as macrophages, lymphocytes, neutrophils, mast cells, and platelets create an inflammatory environment that attracts other immune cells, resulting in the erosion of the joint. 

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Figure 8: A rheumatoid arthritis nodule

Figure 8: Shows a rheumatoid arthritis nodule (a symptom of RA) that contains collagen (stained blue towards the bottom) and surrounding it is macrophages or dendritic cells (types of immune cells).