The Staining of Mast Cells: A Historical Overview.

The specificity of several staining methods for mast cells provides the pathologist with a useful means for the differential diagnosis of mast cell tumors. Mast cells stain metachromatically with toluidine blue with greater intensity in cells containing smaller granules. Most stains for mast cells rely on the cell's content of heparin, other glycosaminoglycans, and esterase. As an alternative to histochemical stains, different antibodies have been used to identify mast cells in humans.