A man died 8 days after the onset of the disease. He was

diagnosed with dysentery. On the autopsy, a thickened wall of the sigmoid colon

and rectum was found. There was a fibrinous membrane covering the surface of

the mucous membrane. Histologically, profoundly penetrating necrosis of the

mucous membrane was observed. Necrotic masses were infiltrated by fibrin. What

type of colitis did the patient have?