A 73-year-old male comes to your office with a 3-day history…
A 73-year-old male comes to your office with a 3-day history of left lower quadrant abdominal pain. He has felt cold and clammy at times but has not checked his temperature. He has had no nausea, vomiting, or diarrhea. The pain does not worsen after meals, but his appetite has been poor since this started. On review of systems, he reports increased urinary frequency and urgency for the same amount of time. He has had no abdominal surgeries. He has diabetes mellitus type 2 and is on metformin. He also takes aspirin 81 mg/day. He has always declined screening colonoscopy, stating, “If it ain’t broke, don’t fix it”—apparently, his family motto. On examination, he is in no distress with blood pressure 125/75 mm Hg, pulse 90 bpm, respirations 15, and temperature 38.5°C. His heart sounds are normal, and his chest is clear bilaterally. He has moderate left lower quadrant tenderness without rebound tenderness or guarding. There is no abdominal distention or organomegaly. Bowel sounds are normal, and the rectal examination is normal without stool in the rectal vault. Urinalysis is normal.What is the most likely diagnosis?