Differential histologic diagnosis of osteoid. A study on human osteosarcoma collagen by the histochemical picrosirius-polarization method.

Using only one histologic preparation and under the light microscope, the simple method described here permits a distinction between osteoid and other tissue components that can be mistaken for osteoid. Osteoid from both normal osteogenesis and osteosarcomas is disclosed by the picrosirius-polarization method as a three-dimensional network of randomly arranged, thin, short, weakly birefringent collagenous structures which shine against a dark background. These morphologic features can be used as a precise diagnostic criterion for the differential diagnosis between osteoid and other materials which resemble osteoid by other staining techniques. This precise characterization of osteoid is of great importance since the presence of osteoid is used as a criterion for the differential diagnosis of osteosarcomas. Not only does this method permit the precise characterization of osteoid but it is also useful for studying collagen distribution in osteosarcomas. In this regard the foregoing results agree with the immunofluorescence observations recorded in the literature.