Which staining method is most likely used when collagen stains blue in the image?

• A. Gomori
• B. Masson
• C. Verhoeff-van Gieson
• D. Bouin solution

Answer: (B)

Blue staining of collagen is a hallmark of Masson trichrome staining. This method uses aniline blue to color collagen fibers blue, while muscle and cytoplasm take shades of red or pink and nuclei appear dark. The image’s blue collagen aligns with Masson’s color scheme, distinguishing it from other stains. For example, Gomori trichrome typically colors collagen green or greenish-blue, Verhoeff-van Gieson yields collagen pink while elastic fibers are black, and Bouin solution is a fixative used in tissue processing rather than a stain that specifically produces blue collagen.