Which stain is described as a connective tissue stain in the material?

• A. Masson Trichrome
• B. Phosphotungstic acid-hematoxylin
• C. Verhoeff-van Gieson
• D. Oil Red O

Answer: (A)

Masson Trichrome is designed to distinguish connective tissue by highlighting collagen fibers distinctly from other tissue components. It uses a combination of dyes that color collagen blue (or green, depending on the variant), while muscle and cytoplasm stain red and nuclei stain dark. This clear separation makes fibrous tissue and fibrosis easy to identify, which is why it’s described as a connective tissue stain.

The other stains target different elements: phosphotungstic acid-hematoxylin emphasizes muscle fibers and striations; Verhoeff-van Gieson highlights elastic fibers; Oil Red O stains lipids in frozen sections. They don’t selectively stain collagen the way Masson Trichrome does, so Masson Trichrome is the best choice for visualizing connective tissue.