Author: Dr Ben Tallon, Dermatologist/Dermatopathologist, Tauranga, New Zealand, 2011.
This tumour is grouped within the benign mesenchymal tumours.
Histology of giant celltumour of tendon sheath
Scanning power view of giant celltumour of tendon sheath identifies a well circumscribedtumournodule arising in the deep dermis or subcutis (Figures 1-3). The tumournodule is comprised of a population of oval cells set in a minor condensed eosinophilic fibrous stroma (Figures 4 and 5). Scattered multinucleatedgiant cells are present (Figure 6). In most cases small clusters of lipid laden cells can be seen (Figures 7 and 8) .
Special stains used for giant celltumour of tendon sheath
Giant celltumour cells stain positively for CD68 and Vimentin suggesting a fibrohistiocytic origin.
Differential diagnosis of giant celltumour of tendon sheath
Giant celltumour of soft tissue: This tumour is typically a larger multinodular tumour. There may be notable stromal vasculature and deposits of metaplastic bone. Special stains can be positive for both smooth muscle actin and alkaline phosphatase, not typically seen in giant celltumour of tendon sheath.
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