A 57-year-old female presented with a five-year history of non-bloody diarrhea, reaching 10 to 20 daily depositions without abdominal cramping and a weight loss of 25 kg. Past medical history was significant for rheumatoid arthritis treated with rituximab during the last six years. All her previous endoscopic and histological studies identified lymphocytic infiltration. Previously, she received treatment with rifaximin, cholestyramine, and loperamide without improvement.
