Verhoeff\'s Van Gieson technique: prolonged exposure to sodium thiosulfate can lead to which outcome?

• A. Background appears muddy
• B. Nuclei fade
• C. Tissue shrinkage
• D. Overstaining of collagen

Answer: (A)

In Verhoeff–Van Gieson, sodium thiosulfate serves as a decolorizing step to remove excess hematoxylin after the elastic fibers have been stained, so that elastic fibers appear black against a contrasting background colored by the Van Gieson counterstain. If this decolorizing step is prolonged, too much stain is removed from non-elastic tissue, which blurs the distinction between the background and the stained elements. The result is a background that looks muddy and lacks crisp contrast, making it harder to interpret the elastic fibers against the rest of the tissue.

Nuclei fading can occur with aggressive decolorization in some protocols, but the hallmark consequence described here is a muddy background. Tissue shrinkage and overstaining of collagen are not expected outcomes from extending this specific decolorizing step.