Figure 10a. High-grade diffuse large B-cell lymphoma of the ileocecum in a 57-year-old man who presented with a 3-week history of right iliac fossa pain. (a) Contrast-enhanced CT scan obtained at the level of the right iliac fossa shows irregular thickening of the terminal ileum and the cecum with stranding in the adjacent mesentery. The posterior aspect of the ileocecal valve (arrow) is distended and thin compared with the anterior wall, although no definite perforation was identified at CT. Histologic analysis showed localized perforation at the site. (b) Contrast-enhanced CT scan obtained caudad to a shows concentric wall thickening of the terminal ileum (arrow) with stranding in the adjacent mesentery. Fluid-filled distended ileal loops (S) are also identified in the pelvis. (c) Low-power photomicrograph (original magnification, x4; H-E stain) shows infiltration of the bowel wall (short arrow) by tumor (long arrow).