A 50-year-old man with a history of anemia and kidney stones presented to the emergency room complaining of persistent lower abdominal pain, fever, and chills. Three days earlier, he presented to his primary care physician with complaints of fever (102°F), nausea, vomiting, and watery diarrhea. He reported increased abdominal distention for the past 4 months, despite his attempts to diet and lose weight. A computed tomography (CT) scan of his abdomen revealed the diagnosis (Figure).