Diagnosis is right, but located in left : acute appendicitis

A 69-old man was admitted to emergency service with abdominal pain and nausea which had lasted for three days. He explained that abdominal pain began as periumbilical area and migrated to left side of umbilicus. He denied any history of abdominal surgery or chronic disease. Muscular defense and rebound were found on the left side of umbilicus in abdominal examination. Vital signs were insignificant except for a fever of 38.6°C. Urine analysis was normal. Hemoglobin count was 14.4 g/dL and white blood cell count was 14160/mm3. C reactive protein was 27.39 mg/dL. Abdominal X-ray and ultrasonography (US) was unremarkable. Abdominal computed tomography (CT) scan revealed left-sided caecum with pericaecal inflammatory changes due to acute appendicitis