Which stain highlights collagen fibers in connective tissue?

• A. Masson's Trichrome
• B. Papanicolaou
• C. Toluidine blue
• D. Luxol fast blue

Answer: (A)

Masson's Trichrome is designed to differentiate connective tissue components, making collagen fibers stand out clearly. In this stain, collagen takes a blue (or green, depending on variant) color, while muscle and cytoplasm stain red and nuclei appear dark. This contrast lets you easily visualize the amount and organization of collagen within connective tissue, which is essential for assessing fibrosis or structural integrity.

The other stains don’t target collagen specifically. Papanicolaou is a cytology stain used for exfoliated cells, not for detailed connective tissue architecture. Toluidine blue is a basic dye that highlights general tissue features and can show mast cells and certain granules but doesn’t selectively emphasize collagen fibers. Luxol fast blue is used mainly to stain myelin in nerve tissue and related structures, not collagen.