A study on the histogenesis of giant cell tumor of bone - Histochemical and tissue culture studies.

Giant cell tumor of bone was studied with hitochemical and tissue culture techniques, in reference to its histogenesis. Mononuclear stromal cells were mainly composed of histiocytic cells, and addingly the various cells on a fibroblastic line of differentiation, i. e. giant cell tumor of bone was considered to originate from undifferentiated mesenchymal cells showing the bimodal but predominantly histiocytic differentiation. Depending on the circumstances, fibroblastic differentiation might be dominant or metaplasia of histiocytic cells to fibroblastic cells might occur. As to multinucleated giant cells, they could not be clarified neoplastic or reactive. However, there was no relation of nuclear atypism between the multinucleated giant cells and stromal cells, and therefore it is proper to consider that monouclear cells are the principal tumor cells and histological grading should be based on their atypism.