Figure 2. (A) H&E, 10×: Neuroendocrine tumor, grade 1 (carcinoid) at tip. Large and small nests composed of polygonal cells with salt-and-pepper chromatin and cytoplasmic brightly eosinophilic basally-located granules (insert; H&E 200×). Muscularis propria and subserosal tissue were infiltrated. In immunohistochemistry analysis (not shown), these cells were positive for chromogranin-A and synaptophysin. No mitosis was observed, and the Ki-67 proliferation index was less than 1%. (B) H&E 10×, and (C) H&E 100×: Low-grade appendiceal mucinous neoplasms (LAMN). At the corpus, the lumen was dilated by mucus accumulation. Mucosa-associated lymphoid tissue was absent. The normal mucosa was replaced with an undulating epithelial monolayer of uniform columnar cells with apical mucin and basal hyperchromatic nucleus. Muscularis mucosae were maintained. (D) H&E 10×. On subsequent right hemicolectomy, the specimens showed a residual appendix partially occluded by extensive fibrosis. The lumen was filled with acellular mucus. In the caecum wall there was a lake of extracellular mucus in the submucosa without evidence of epithelial cells.