HI I work in gastro and you should not worry. So, they found fecal fat in your stool. I actually went through the same thing and never got an answer (i am a patient and i also work there). For me, my small bowel biopsy when i had upper endoscopy looked like celiac disease becuase i had crypt hyperplasia and increased duodenal IELs so i was Marsh 2. IN the differential it could be systemic autoimmune disease, SIBO, NSAID use, H pylori, celiac, crohn's. Well i was negative for everything and don't use NSAIDS so i never got an answer. I do not carry DQ2 and DQ8 genes therefore i cannot have celiac. I don't use Nsaids. I had lactulose breath test which came back suggestive of small bowel bacterial overgrowth. That's only suggestive. So i never got a real answer. I have had WBCs in my stool and fecal lactoferrin high... that is seen in inflammatory bowel and infections... but my colonoscopy with random biopsies is completely negative. I had my stool checked for fecal fat and it was negative. I know what you are going through and you may never get an answer. I never fully got a definitive answer. Very frustrating. So i just do my own thing and eat healthy. The answers aren't out there for people with weird problems because science is just not there yet. Since they found fecal fat in your stool it has nothing to do with cancer. It's more from malabsorption or that the pancreas is not producing as many digestive enzymes. That happens with age, with alcohol abuse, with people that have high triglycerides/cholesterol... obese people that continue to eat a high fat diet, cystic fibrosis, stuff like that. Your problem could be as simple as just taking a pancreatic enzyme supplement to help you digest fats in foods. Since you are gluten free.. the only test you could do to exclude a celiac possibility would be genetic markers for it to see if you carry DQ2 and DQ8 genes, but even if you do, that is still not definitive unless you also have a biopsy for it, and for that, you would also need to go back on gluten and then biopsy. It sucks when you have strange problems. I have very odd problems, and i work in the medical field, and i know the answers just aren't there fully and it is very frustrating. SO i gave up trying and now i just do my own thing... eat clean and healthy, avoid what bothers me, and do stretching and stuff like that.