The brown pigment in formalin-fixed tissue is especially heavy in which areas?

• A. Bloody areas
• B. Fatty areas
• C. Glandular areas
• D. Basal layers

Answer: (A)

This question hinges on recognizing hemosiderin, the iron-containing brown pigment that appears after red blood cell breakdown. When tissue has bled, macrophages take up the iron and store it as hemosiderin, which gives a golden-brown to brown granular appearance. Because hemosiderin marks sites of prior hemorrhage, it is especially heavy in bloody areas.

Other brown pigments exist but are not tied to recent bleeding: lipofuscin tends to accumulate with aging and is seen in various cell types, not specifically in fatty areas, while melanin and other pigments localize to particular tissues (like basal epidermal layers) for reasons unrelated to hemorrhage.