H&E STAIN

The majority of tissues are routinely stained with hematoxylin-eosin (H&E). Hematoxylin stains the nucleus, while eosin stains the cytoplasm, and various extracellular materials. Hematoxylin comes from the bark of a tropical wood, found in Mexico, Haematoxylon campechianum. It is subsequently oxidized prior to being used. Eosin is an anionic xanthene dye that combines through electrostatic charges with various cytoplasmic materials. In addition, eosin binds most tissues, such as collagen and muscle, making them look pink. In pathology, a common saying is “dark (hematoxylin – nuclei = highly replicating cells, like in a tumor) is bad, and pink is dead (eosin – collagen, protein).”

The H&E is the most commonly used stain in the world. It allows for a great microscopic examination and diagnosis of the majority of tissues sent to pathology. Unfortunately, the H&E stain is insufficient to answer all of a pathologist’s questions. Therefore, numerous additional stains, termed “special stains” are routinely used by pathologists, to help differentiate different tissues and disease processes, and come to better conclusions.

There are hundreds of special stains, here we will talk about the most common.

PAS

PAS, periodic acid-Schiff stain, is one of the most helpful stains. This stain reveals glycogen, mucosubstances, and basement membranes. In addition, parasites and fungi can also be revealed.

Other stains:

Argentaffin and argyrophilic stains Rosai