Q96
Single choice
A65-year-old man presents with a 4-day history of worsening lower abdominal pain and constipation. On examination, he is febrile (38.5°C) and has lower a bdominal tenderness that is most intense in the midline and left lower quadrant associated with a palpable fullness. Laboratory findings demonstrate a moderate leukocytosis and abdominal roentgenograms show an ileus pattern. For the above patient with abdominal pain, select the most likely diagnosis.