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Fibroma and giant cell
tumor of tendon sheath: a comparative histological and immunohistological
study.
Mod Pathol. 1995 Feb;8(2):155-9.
Giant cell tumor of
tendon sheath (GCTTS; "nodular tenosynovitis") and fibroma of tendon sheath
(FTS) have traditionally been considered to be two points in a single
neoplastic continuum. However, no systematic studies have addressed this
concept directly to date. To more clearly define their relationship to one
another, we studied five FTSs and seven typical GCTTSs by light microscopy
and paraffin section immunohistochemistry. Tissue samples were stained for
vimentin, desmin, smooth muscle actin (SMA), S100 protein, leukocyte common
antigen (CD45), CD68 antigen (KP1), HAM56 antigen, alpha-1-antichymotrypsin
(AACT), and MAC387 antigen. These reagents were chosen to address proposed "fibrohistiocytic"
and myofibroblastic lineages for the two lesions. All tumors had a lobular
appearance. GCTTS was more cellular than FTS; it contained conspicuous
numbers of osteoclast-like cells, and the stroma was not extensively
hyalinized. In contrast, FTS was matrix-rich, often with extensive stromal
sclerosis, and contained only rare giant cells. Immunophenotyping of GCTTS
showed that both the spindle cell and giant cell components were positive
for vimentin, LCA, CD68, HAM56, AACT, and MAC387, suggesting monocyte-macrophage-like
features. Limited reactivity for desmin and SMA also implied conjoint
myofibroblastic differentiation. On the other hand, FTS showed focal
staining with HAM56 (all cases) and for CD68 (one case); staining for
vimentin and SMA was uniformly intense and diffuse. Based on these results,
we conclude that GCTTS and FTS both exhibit varying degrees of monocyte-macrophage-like
and myofibroblastic differentiation. The predominance of macrophage-related
determinants in GCTTS and myofibroblastic markers in FTS supports the
premise that these lesions represent phenotypic extremes of a single
clinicopathologic entity. |