Question: A 58-year-old man with unremarkable past medical history presented at the emergency department of our hospital for low-grade fever and dull right lower abdominal pain. On arrival, his abdomen was mildly tender and his body temperature 38.2°C; routine laboratory tests showed leukocytosis (12.7 × 109/L; normal range, 3.5-10.5 × 109/L) and increased level of C-reactive protein (2.6 mg/dL; normal range, 0-1). A plain abdominal radiograph was normal; abdominal ultrasonography (US) revealed a moderate thickening of the ileal walls in the right iliac fossa.