Chronic diarrhea and weight loss.

Question: A 61year-old black man with a past medical history of hypertension, hyperlipidemia, and coronary artery disease presented in January 2013 for evaluation of chronic nonbloody diarrhea and weight loss of 60 pounds over the past 2 years. Associated symptoms included abdominal discomfort, loss of appetite, and fatigue. Current medications included amlodipine, budesonide, pravastatin, olmesartan, and aspirin. An extensive evaluation including routine laboratory tests, stool cultures, stool ova þ parasites, stool analysis, Clostridium difficile polymerase chain reaction, celiac panel (immunoglobulin A/TTG), thyroid-stimulating hormone, immunoglobulin, serum protein electrophoresis, plasma peptides (gastrin, calcitonin, vasoactive intestinal peptide, somatostatin), urine 5-hydroxy-indole-acetic acid, and tumor markers (carcinoembryonic antigen, carbohydrate antigen19-9, alfa fetoprotein) were unremarkable. Fecal fat was 19 g over 24 hours. He was started on trial of pancreatic enzymes without clinical benefit. Glucose breath test was negative for small bowel bacterial overgrowth. Further diagnostic testing including computed tomography of the abdomen and small bowel follow through excluded structural disease. He was subsequently diagnosed with lymphocytic colitis as per biopsies done on colonoscopy in October 2012 and was treated with oral budesonide. He noticed slight improvement in diarrhea, but continued to experience loss of weight and decreased appetite. Endoscopic ultrasonography, to rule out chronic pancreatitis, was normal. Esophagogastroduodenoscopy with gastric and duodenal biopsies done in 2012 are shown in Figures A and B, respectively. What is the diagnosis? Look on page 591 for the answer and see the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI.