Which stain is particularly used to visualize elastic fibers and mast cells?

• A. Gomori's Aldehyde Fuchsin
• B. Cresyl Echt Violet
• C. Giemsa
• D. Congo red

Answer: (A)

The main idea is recognizing which stain can reveal both elastic fibers and mast cells in tissue sections. Gomori's Aldehyde Fuchsin is a special stain that strongly highlights elastic fibers, making them dark purple–black against the rest of the tissue. It also stains mast cell granules, allowing these cells to be seen in the same section. This combination is why it’s the best choice for visualizing both structures together.

Cresyl Echt Violet mainly stains Nissl material in neurons, not elastic fibers or mast cell granules. Giemsa is a general cytological stain useful for blood cells and some parasites but does not specifically emphasize elastic fibers or mast cells. Congo red binds amyloid and is assessed by birefringence under polarized light, not for elastic fibers or mast cells.