Romanowsky staining in cytopathology: history, advantages and limitations.

If the entire discipline of diagnostic cytopathology could be distilled into a single theme, it would be the Papanicolaou stain. Yet it was the Romanowsky stain upon which the discipline of cytopathology was founded. Both stains are used today in the cytopathology laboratory, each for a different and complementary purpose. We trace the history of cytopathological stains and discuss the advantages and limitations of Romanowsky-type stains for cytological evaluation. We also provide suggestions for the advantageous use of Romanowsky-type stains in cytopathology.