GIANT-CELL TUMOR OF TENDON SHEATH AND PIGMENTED VILLONODULAR SYNOVITIS - IMMUNOPHENOTYPE SUGGESTS A SYNOVIAL CELL ORIGIN

Giant cell tumor of tendon sheath (GCTS) and pigmented villonodular sy novitis (PVNS) are common synovial ''tumors.'' Their immunohistochemic al profile, however, has not been well characterized, and uncertainty exists regarding their histogenesis and relationship to fibroma of ten don sheath. In an effort to clarify these uncertainties and to better define the immunohistochemical profile of GCTS/PVNS, we examined forma lin fixed tissue from 35 specimens of GCTS, 12 specimens of PVNS, and three cases of reactive synovitis using avidin biotin complex (ABC) an d streptavidin immunohistochemical methods. Antibodies to vimentin, CD 68, HAM56, cytokeratins, EMA, S100, HMB45, leukocyte common antigen, C D34, desmin, and smooth muscle actin were used in the study. The proli ferating mononuclear cells and surface synovial cells in GCTS/PVNS and reactive synovitis: stained positively for CD68, HAM56, and vimentin only. Multinucleated cells stained for CD68, vimentin, and leukocyte c ommon antigen. Ah other stains were negtive. Our results suggest that GCTS/PVNS are tumors of synovial cell origin, and do not support an as sociation between GCTS and fibroma of tendon sheath. Copyright (C) 199 5 by W.B. Saunders Company