H&E and Special Stains

The histopathology laboratory in our department takes care of these services. Hematoxylin and eosin (H&E) is a differential stain and is very useful for studying histologic morphology in sections. In the histopathology laboratory, it is used as a routine stain for staining paraffin and cryosections. Hematoxylin stains the nuclei of cells blue to bluish-purple and eosin stains other cellular elements in the tissues from pink to red.

A low power photomicrograph of an H&E stained paraffin section showing cancer of the colon-note the morphologic difference between the normal colonic glands(region N) and the cancerous glands(region C) in the section.

A higher power photomicrograph showing cancerous glands of colon- the H&E stains nuclei of cells bluish-purple and other tissue elements pink.

Special Stains

Special staining consists of a wide variety of stains that permit the visualisation of microbes, intracellular and extracellular products not easily observed on H&E stained tissue sections. They serve to identify these agents for definitive pathological diagnosis. Examples of such stains include :

PAS( McMannus' Periodic acid schiff's) stain- for visualisation of glycogen in tissues

Southgate's mucicarmine -for localisation of mucin secretion in epithelial and connective tissues

Ziehl-Neelsen- for the demonstration of acid-fast bacteria belonging to the genus Mycobacterium. It serves as a diagnostic tool for the localisation of Mycobacterium tuberculosis, an infectious agent that causes tuberculosis.

The photomicrograph shows a caseous granulomatous lesion in a lymph node and the causative agents are not decernible in the H&E stained section. The inserted image(righthand corner) shows the section following a Ziehl-Neelsen acid-fast special stain viewed under an oil objective. The pink rod microbes,the causative agents engulfed in the giant cells, are Mycobacteria tuberculosis.