Orange is not a common color in cytology... 🍊

You don't see the color orange everyday in cytology.

That is, unless you look at a lot of bleeding lesions/masses!

Hematoidin is a g-o-r-g-e-o-u-s orange, typically rhomboid crystal that looks like this:


So what is it? Hematoidin is a red blood cell breakdown product. 

Macrophages gobble up RBCs, break them down, and voila, you end up with hematoidin crystals. 

Why would you see these?

I thought you'd never ask. 

You see them when there has been previous/chronic hemorrhage

Any process that's causing bleeding into a mass or body cavity can result in the formation of hematoidin crystals. 

Can you think of some pathologies where you might see this?

This particular case was from a salivary mucocele, which commonly involves chronic hemorrhage...and thus, hematoidin crystals.