Tumor of the day: GIST

My job makes me wish I was a better artist because things like these are worthy of watercolors, no matter how tragic they may be:

The detail never looks quite right outside a microscope

You can see a bit of gastric epithelium in the bottom part, at the center. This is a low-power view of a GIST (gastrointestinal stromal tumor), spindle pattern. It's a sarcoma of the gastrointestinal tract, originating from the interstitial cells of Cajal, which are the pacemakers of the gastrointestinal tract. At high power, they look this:

GIST, spindle cell pattern

These cells stain with DOG1 (discovered on GIST) and CD117, and other stuff I'm not remembering off the top of my head.