Chapter 30: Histologic Stains and Special Studies

HEMATOXYLIN AND EOSIN (H&E)

Used for elucidation of basic histologic features, prior to the use of special stains or immunohistochemical studies as needed; among other features, calcification and microorganisms such as fungi and bacteria may be detected by H&E and confirmed by additional studies

STAINS FOR CARBOHYDRATES

• Periodic-acid Schiff (PAS)

  • Stains glycogen red—diastase labile; therefore, diastase pretreatment will remove glycogen

  • Stains mucopolysaccharides red—diastase stable

  • Stains fungi red—diastase stable

  • Stains basement membrane red—diastase stable

• Colloidal iron

  • Stains mucin blue

• Alcian blue

  • Stains mucopolysaccharides blue

    • – At pH 2.5: acid (carboxylated or sulfated mucopolysaccharides)

    • – At pH 1.0: acid (sulfated mucopolysaccharides)

    • – With hyaluronidase: only epithelial mucins will stain (connective tissue mucins will be digested and will not stain)

  • With PAS: acid mucopolysaccharides will stain blue and neutral polysaccharides will stain magenta; also, the yeast of Cryptococcus will stain red and the capsule will stain blue with this method

• Mucicarmine

  • Stains epithelial mucins red (also stains capsule of Cryptococcus red)

STAINS FOR PIGMENTS

• Fontana-Masson (Fig. 30-1)

  • Stains melanin and argentaffin granules black (nuclei will be red); useful for quantifying melanocytes (e.g., in vitiligo) and in cases of minocycline pigmentary alteration

  • Also stains Cryptococcus and the phaeohyphomycotic organisms

• Grimelius argyrophil stain

  • Argentaffin and argyrophil substances will stain black

• Tyrosinase (DOPA-oxidase)

  • Requires fresh tissue

  • Stains melanin-containing cells brownish-black (due to tyrosinase acting on DOPA, the substrate for this reaction)

STAINS FOR MINERALS

• Von-Kossa

  • Stains calcium salts black; useful for detecting calcification of vessel walls and elastic tissue (calcinosis cutis, pseudoxanthoma elasticum, calciphylaxis, elastosis, and elastofibroma)

• Alizarin red S

  • Stains calcium red

• Prussian blue stain (Fig. 30-2)

  • Stains iron blue (the Prussian blue reaction: tissue treated with dilute hydrochloric acid and potassium ferrocyanide) (Note: if it's granular and staining blue, it's likely an iron stain)

• Gomori methenamine silver (GMS) (Fig. 30-3)

  • Stains urates (e.g., gout) black. (Note: urates are lost if tissue is processed in formalin)

  • Tissue must be processed with alcohol to prevent loss of urates

  • Also see section "Stains for Microorganisms"

STAINS FOR CONNECTIVE TISSUE COMPONENTS

• Trichrome

  • Stains collagen blue or green and muscle red, depending on the type of reagents used

• Verhoeff-van Gieson

  • Stains elastic fibers black, collagen red, and muscle yellow (also red cells will stain ...