The main tool and base microscopic examination of the surgical pathology is the hematoxylin-eosin staining of histological slides after fixation of tissue in formalin, paraffin embedding obtaining sections of 5 microns using a microtome.
In the technique of H & E., Staining of nuclei in blue with hematoxylin contrast is followed cytoplasm and several extracellular components in red with eosin.
This technique allows a correct microscopic diagnosis of most of the samples sent to the laboratory.
However, this technique can not answer all the questions posed by a particular case in terms of diagnosis and is clearly inadequate in terms of histogenesis, etiology or pathogenesis. As a result, the pathologist has always sought additional techniques to try to clarify these questions.
Colloquially these techniques are called “special” simply because they are used only in special circumstances.
I. Special Stains
Of the hundreds of special stains that appear in the classical texts of microscopic technique, the surgical pathologist found a few really useful today. Especially since the widespread use of immunohistochemistry.
The most used are:
1. PAS (periodic acid-Schiff)
2. Stains for microorganisms
3. Stains argentaffin and argyrophilic
4. Staining amyloid
5. Reticulin stain
6. Trichrome Staining
7. Stains for hemosiderin (Perls)
8. Stains for calcium (von Kossa)
9. Giemsa stain
10. Elastic fibers