Mucicarmine stain

Mucicarmine stain is a staining procedure used for different purposes. In microbiology the stain aids in the identification of a variety of microorganisms based on whether or not the cell wall stains intensely red. Generally this is limited to microorganisms with a cell wall that is composed, at least in part, of a polysaccharide component. One of the organisms that is identified using this staining technique is Cryptococcus neoformans.^[1]

Histopathology of signet ring cell carcinoma of urinary bladder on mucicarmine stain, coloring the mucin within tumor cells pink/red.

Another use is in surgical pathology where it can identify mucin. This is helpful, for example, in determining if the cancer is a type that produces mucin.

Example would be to distinguish between high grade Mucoepidermoid Carcinoma of the parotid, which stains positive vs Squamous Cell Carcinoma of the parotid which does not.