Indolent T-LPD of the duodenum (case 9). (A) A dense infiltrate involving the lamina propria, muscularis mucosae, and submucosa. (B) The infiltrate is composed of small lymphoid cells with slightly irregular nuclei and occasional admixed eosinophils. Immunohistochemical stains for (C) CD4 and (D) CD8 show the lymphoid cells to be predominantly CD8-positive and focally involve the villous epithelium. (A: H&E, original magnification ×40; B: H&E, original magnification ×400; C-D: immunohistochemical stain, original magnification ×100.)