This case of acute appendicitis was missed on initial CT interpretation perhaps because the reader did not consider differential diagnoses beyond the clinical impression of acute diverticulitis. Looking in the pelvis for free fluid (any free fluid in a male patient is abnormal) and attempting to identify the appendix are two essential tasks to perform when assessing a CT in the setting of acute abdominal pain. Surgery was unfortunately delayed in this patient and his post-operative course was complicated by a fluid collection at the surgical site that required drainage.