Clinical and Morphological Correlations and Histopathology of Joint Damage in Patients With Diffuse-Type Tenosynovial Giant Cell Tumor

Abstract

Introduction: Tenosynovial giant cell tumor (TSGCT) (synonym – pigmented villonodular synovitis) – is a rare benign proliferative lesion of the synovial sheath, localized in the joint capsule, bursa or tendon sheath and characterized by locally destructive growth. Depending on the prevalence within the joint elements, the presence of a capsule around the tumor, histophotographic features of cell structure and clinical behavior TSGCT can be divided to localized or diffuse type. The aim of the study was researching of histopathological properties of diffuse-type TSGCT, determine the parameters its morphological indicators and to find out the correlation between these morphological and clinical parameters. Materials and methods: The research material was used biopsy (resect) of pathological lesions from 50 patients who were diagnosed and histologically verified diffuse-type TSGCT. Microscopic examinations of the stained sections and their photo archiving were carried out with use of a Olympus-CX 41 light optical microscope. Group measurable parameters (mean values and Pearson tetrachoric index (association coefficient) were calculated in groups of comparison for morphological and clinical indices of TSGCT. The mean values were compared by Student’s test, P value of ≤0.1 was considered statistically significant. Results:Correlation analysis of indicators that accounted for the pairs of cases «clinic – morphology» revealed the relationships, that had the highest parameters of the association coefficient between such indicators: «presence of villous growths» - «severity of hemosiderosis» (if hypertrophied synovial villi available, with vascular injection and pronounced proliferation of synovial cells, there is also a significant accumulation of hemosiderin pigment); «presence of villous growths» - «type of predominant cellular proliferates» (if cells of TSGCT diffuse type consists of monotonous sheets of stromal cells, with uniform, oval to reniform nuclei, the proliferation of villi in synovial layer is non-distinctive); «presence of nodes» - «kind of stroma» (if nodes predominate, their histological structure is mainly represented by polymorphic clusters of synovitis cells in the form of cells, strands, chains, solid formations, among immature connective tissue with low hyalinosis); «cell size (area, cm²)» - «severity of haemosiderosis» and «cell size (area, cm²)» - «the number of multinucleated giant cells» (there is a pronounced deposition of pigment and accumulation of osteoclast-like multinucleated giant cells type, although usually their number is relatively small compared to the localized type of TSGCT). Conclusions: Morphological parameters, that we have identified, characterize pathological changes in the tissues of TSGCT; careful analysis of the frequency of their occurrence in the different comparison groups made it possible to establish intergroup differences and correlations between individual indicators, which were previously unknown or not obvious. Our study was determine to analyze of incidence rates and correlation relationships, revealed some previously unknown differences and dependencies that are important for understanding the pathogenesis, improvement of diagnosis and prognosis of diffuse-type TSGCT.