Giant cell fibroblastoma of soft tissue: a clinicopathological and immunohistochemical study.

Giant cell fibroblastoma is an uncommon, benign tumour of soft tissue which was first described in 1982. Thirty-five cases have been previously published. Six new cases are reported herein, which have also been examined immunohistochemically for the expression of vimentin, desmin, myoglobin, S-100 protein, neurofilaments, Factor VIII related antigen and binding of the lectin Ulex europaeus. The previous literature has been reviewed. Giant cell fibroblastoma most often presents in early childhood as a slowly growing, infiltrative subcutaneous mass at a wide variety of sites. It shows a predilection for males and may recur locally in up to 50% of cases. The very distinctive histological features, characterized by so-called solid and angiectoid areas, are presented. The tumour cells were vimentin positive but negative for all other markers used. In particular, there was no evidence of endothelial differentiation. The histogenesis of this unusual tumour is discussed in the light of previous ultrastructural findings.