HISTOPATHOLOGICAL SCALE AND SYNOVITIS ALGORITHM – 15 YEARS OF EXPERIENCE: EVALUATION AND FOLLOWING PROGRESS

Abstract

The diagnostic histopathology scales are mainly the multilevel evaluation systems. The same principle is lying in the basis of synovitis scale elaboration. This scale gradually and semi-quantitatively assesses the inflammatory and immunological changes in case of synovitis considering three synovial components: thickness of synovial cellular layer, cellular stroma density and severity of inflammatory infiltration. The scale comprises four semi-quantitative grades: normal 0, mild, moderate and severe. Scale points from 0 to 9 are summated. Such sum evaluation allows to identify high and low degree synovitis. Scale points from 1 to ≤4 correspond to low degree synovitis which determines and includes the following diagnosis: arthritis associated synovitis; synovitis associated with meniscus pathology; hemochromatosis associated synovitis. Scale points from ≥5 to 9 determine high degree synovitis including diagnosis like rheumatoid arthritis; psoriatic arthritis; Lyme arthritis; post infection (reactive) arthritis and peripheral arthritis in Bekhterev’s disease. Thus, the synovitis scale allows to assess degenerative or posttraumatic (low degree synovitis) and inflammatoryrheumatoid pathology (high degree synovitis) based on histopathological diagnostics with sensitivity of 61,7% and specificity of 96,1%. The scale is characterized by a good diagnostics significance by ROC analysis (area under curve: 0,8–0,9). Two versions of synovitis scale was published: first in 2002, second reworked in 2006 and the latter includes the concept of subdivision into two groups of high and low degree synovitis. Thanking to both versions a national and international recognition of histological evaluation during 15 years was gained. To clarity diagnosis description using synovitis scale particularly in rheumatology various inflammatory antigens were suggested for immunohistochemical analysis (including Ki-67, CD68-, CD3-, CD15и CD20). This immunohistochemical scale and subdivision into low and high degree synovitis provided a possibility to assess the risk of development and biological sensitivity of rheumatoid arthritis. Thus, an important histological input was made into primary rheumatology diagnostics which did not consider tissue changes. Due to formal integration of synovitis scale into the algorithm of synovial pathology diagnostics a comprehensive classification was developed specifically for differentiated orthopaedics diagnostics.

Keywords

• synovitis
• synovitis scale
• rheumatology arthritis
• semi-quantitative evaluation
• immunohistochemistry
• risk stratification