In small intestine sections, orange goblet cells partially obscured by a yellow background are most likely due to overstaining with which dye?

• A. Metanil yellow
• B. Eosin
• C. Hematoxylin
• D. Crystal violet

Answer: (A)

Overstaining with a yellow dye can shift colors in tissue sections so that goblet cell mucin appears orange while the surrounding background becomes yellow. Goblet cells contain mucins that can take up certain dyes differently from the surrounding tissue, and metanil yellow is a yellow-orange dye that, when used in excess, accentuates both the orange color in the goblet cell contents and a yellow background. The other dyes produce colors that don’t match the observed pattern: eosin colors cytoplasm pink to red, hematoxylin colors nuclei blue, and crystal violet yields purple. So the orange goblet cells with a yellow backdrop point to overstaining with metanil yellow.