Question: A 60-year-old man with a 5-year history of intermittent diarrhea had been experiencing approximately 5 episodes a day when he visited our hospital. The diarrhea was watery, and he had no abdominal pain, but slight edema was noted in his lower legs. Blood test results revealed decreased albumin level of 1.5 g/dL, normal C-reactive protein level, and increased serum-soluble interleukin-2 receptor (sIL-2R) level of 1443 U/mL. Upper gastrointestinal endoscopy revealed many small white nodules throughout the esophagus (Figure A), and the duodenal mucous membrane was edematous and rough (Figure B).