Masson's trichrome stain is a three-color staining protocol used to distinguish collagen from smooth muscle in histological samples. It works by using acid and dye solutions to differentially stain collagen fibers green and smooth muscle/cytoplasm red. The stain is commonly used to identify increased collagen deposition, such as in conditions like collagenous colitis that involve thickening of the subepithelial collagen layer in the intestine. When applied to samples, nuclei appear black/blue, muscle and cytoplasm appear red, and collagen appears green under microscopy.

2. MASSONS TRICHROME STAIN PRESENTED BY: MEHTAB SHAH B.S MT 3 Rd year (SDLS(LNH) HISTOPATHOLOGY

11. FIXATIVE Bouin’s solution is preferred 10% neutral buffered formalin may be used TECHNIQUE Cut paraffin section at 4 microns

15. Light green solution 2-5mint; Dehydrate in absolute alcohol Clear in xylene Mount in synthetic resin Microscopy

19. Nuclei red, collagen green, cytoplasm red

20. Infracted rat heart showing damaged cardiac tissue in blue.

21. Terminal ileum with increase in subepithelial collagen table in a patient with collagenous colitis