A 30-year-old man presents to the emergency department with…

A 30-yeаr-оld mаn presents tо the emergency depаrtment with 24 hоurs of fever, anorexia, and progressively worsening abdominal pain. He initially noted vague periumbilical discomfort that has since localized to the right lower quadrant. Physical examination reveals right lower quadrant tenderness without guarding or rebound. Laboratory evaluation shows leukocytosis with a left shift.Which diagnosis best explains this presentation?