Masson's trichrome stain

Masson's trichrome is a three-colour staining procedure used in histology.

The recipes emerged from Claude L. Pierre Masson's (1880–1959) original formulation have different specific applications, but all are suited for distinguishing cells from surrounding connective tissue.

Most recipes produce red keratin and muscle fibers, blue or green collagen and bone, light red or pink cytoplasm, and dark brown to black cell nuclei.

It can also be used to detect and analyze tumors on hepatic and kidney biopsies.

[2] This combination is useful for the examination of blood vessels; the Verhoeff stain highlights elastin (black) and allows one to easily differentiate small arteries (which typically have at least two elastic laminae) and veins (which have one elastic lamina).

Masson's trichrome stain of rat airway. Connective tissue is stained blue, nuclei are stained dark red/purple, and cytoplasm is stained red/pink.
Mouse skin stained with Masson's trichrome stain.