Milo has been diagnosed with pancreatic lymphoma, which apparently is incredibly rare.  The vet told me that she only found one documented case of this in veterinary literature.

I'm going to give my little buddy the best shot at beating this.  While the prognosis is uncertain due to the rarity of what he has, lymphomas in cats are very treatable. 

This will likely mean chemo for the foreseeable future until the mass goes away....