Bundles and Bundles and Bundles, Oh My!

Did you know that you can see collagen in mast cell tumors? And sometimes, it's A LOT!

This is a case where there was a ton of collagen present. This happens when collagen is damaged due to degranulating eosinophils releasing collagenase. 

If you've never seen this, it would be easy to confuse these bundles with infectious organisms, like fungal hyphae!