Figure 1.

Morphological aspects of ileocecal surgical specimens with intussusception; (a)–(d) Patient 1 (adenovirus infection); (e) Patient 2 (adenovirus infection); (f) Patient 3 (no adenovirus infection). (a) Ileocecal specimen with polypoid intraluminal tumour nodules (arrowhead). The appendix is marked by an arrow. Barr indicates 1 cm. (b) Transmural tissue section of the terminal ileum displaying lymphoid hyperplasia with diffuse lymphocytic infiltration. H/E; original magnification 50×. (c) Dense lymphocytic infiltrates in strong vicinity to nervous plexus with ganglia (arrowheads). Lymphocytes accumulate in subserosal connective tissues. H/E; original magnification 200×. (d) Anti-CD3 immunohistochemistry demonstrates T-lymphocytes in strong vicinity to the intramural plexus cells (plexus border is marked by dotted line). Small vessels crossing the plexus are marked with arrowheads. Original magnification 400×. (e) Tissue section of the terminal ileum (patient 2) demonstrates the plexus myentericus (dotted line) and several infiltrating lymphocytes and eosinophiles (arrowheads). H/E; original magnification 400×. (f) Transmural ileal tissue section (patient 3, adenovirus negative intussusception) with only mild lymphoid hyperplasia and few infiltrating lymphocytes (the nervous plexus is marked by arrowheads). Inset: Strong accumulation of erythrocytes adjacent to the nervous plexus (dotted line), but morphological features of inflammatory neuropathy are not visible. H/E; original magnification 50×; inset 400×.