A very interesting clinical, roentgenographic, and pathologic lesion is presented which is found terminally in both treated leukemics who are agranulocytic and in patients with terminal aplastic anemias. Pathologically the severe hemorrhagic necrotic lesion of the cecum which is produced causes atonicity and loss of normal haustral markings of the cecum and ascending colon. Because of these pathologic findings, it is possible to suggest a diagnosis of typhlitis roentgenographically. The presence of a large soft tissue density in the right side of the abdomen with small bowel distention and little, if any, colon gas are the common roentgenographic manifestations of typhlitis. The presence of this soft tissue density differentiates typhlitis from appendicitis. The diagnosis of typhlitis carries a grave prognosis. Why this lesion occurs with such severity in this portion of the bowel and not in others is open to question. What part the immune apparatus of the body might play in the formation of this lesion is also open to discussion but no consistent gamma globulin changes have been found in our patients.