True or False: Masson trichrome and van Gieson are used to differentiate smooth muscle from collagen fibers.

• A. True
• B. False
• C. Only Masson trichrome differentiates
• D. Only van Gieson differentiates

Answer: (A)

Both Masson trichrome and van Gieson are used to distinguish smooth muscle from collagen fibers because they create contrasting colors for these tissue components, making their distribution easy to see. In Masson trichrome, smooth muscle and cytoplasm typically stain red, while collagen fibers stain green or blue, depending on the variant, so you can clearly separate muscle from connective tissue. Van Gieson uses a combination of picric acid and acid fuchsin to color muscle yellow and collagen pink, respectively, producing a strong visual distinction between the two. This differential staining is especially helpful when assessing tissue architecture, fibrosis, or tumor invasion where identifying smooth muscle versus collagen is important. So the statement is true.