[@Vicier]

Took a bit of looking into? Your scenario was ripped directly from an episode of House. Season 2 Episode 17, if anyone is interested. The problem with House? It's not medically accurate. A quick wikipedia search told me that diarrhoea, bloody or otherwise, has nothing to do with Erdheim-Chester disease. It affects the heart, lungs and areas of the brain, alongside fucking up your bone marrow. Diagnosis wouldn't involve a colonoscopy either, and "Purple papules"? Papules aren't subcutaneous, they only appear on one's skin, not on the inside of their organs.

Come on, man. If you're going to roleplay a medical professional, at least do your research.