Keep in mind that the body can and does produce materials that can show up on an H&E stain as pigment. Melanin, hemosiderin (old red blood cells), and inflammatory debris can be distracting. Even fixatives can create extracellular pigments, such as Zenker's, which can be concerning if the pathologist is not aware that the sample was fixed in something other than formalin. While Zenker's (potassium dichromate/mercuric chloride) is largely banned due to its toxicity, there are some places that may still make their own. Make a note of any unusual fixation circumstances that could alter staining.
