Which statement is true about Zenker fixation for these stains?

• A. Both require Zenker
• B. Neither require Zenker
• C. Only Gomori reticulin requires Zenker
• D. Only PASM requires Zenker

Answer: (B)

Focus on fixation compatibility with these special stains. Zenker’s fixative is a mercury-based solution that was used historically, but modern protocols for both Gomori reticulin and PASM do not require it. Gomori reticulin relies on silver impregnation to visualize reticular fibers, and heavy-metal fixatives like Zenker can interfere with the silver reaction or create artifacts, so using Zenker is not necessary and can be detrimental. PASM involves periods of oxidation and Schiff reaction to highlight polysaccharides and mucopolysaccharides, and it works well on standard formalin-fixed tissue as part of routine processing; there’s no need for Zenker here either. In practice, both stains are compatible with formalin-fixed tissue, which is why the true statement is that neither requires Zenker.