How do you further workup and treat a patient with nausea and weight loss found to have granulomatous gastritis on endoscopic biopsies with a negative workup for sarcoidosis or Crohn's disease?

Its a good question and challenging scenario. It would be helpful to know a few more details. What was the endoscopic appearance of the stomach, and what symptoms triggered the work up - just nausea and weight loss? How much was the weight loss? How thorough was the work up for Crohn's disease? I as...