Acellular mucin in neoplastic and non-neoplastic conditions of the lower gastrointestinal tract

Figure 1 Acellular mucin in neoplastic conditions. A: Well-differentiated mucinous adenocarcinoma of the transverse colon, inset: Higher magnification view of the tumor [hematoxylin and eosin (H&E)]; B: Serrated adenocarcinoma of the cecum with abundant extracellular mucin, inset: Higher magnification view of the tumoral epithelium with eosinophilic cytoplasm and low nuclear to cytoplasmic ratio (H&E); C: Acellular mucin involving a lymph node in treatment-naïve adenocarcinoma of the right colon, the tumor was microsatellite-high (H&E); D: Acellular mucin pools in the tumor bed of treated rectal adenocarcinoma (H&E), inset shows rare viable tumor cells; E: Low-grade appendiceal mucinous neoplasm of the appendix with acellular mucin extending to the serosal surface through rupture (pT4a), inset: Higher magnification view of low grade epithelium (H&E); F: Pseudomyxoma peritonei of the same patient (E) showing mucin and low-grade epithelium (inset) in the omentum (H&E).

Figure 2 Acellular mucin in non-neoplastic conditions. A: Interval appendectomy with subserosal acellular mucin mixed with inflammatory cells [hematoxylin and eosin (H&E)], inset: Higher magnification view of acellular mucin pools; B: Appendiceal diverticular disease with luminal acellular mucin (triangle) in the diverticulum (H&E); C: Ileum with acellular mucin pool at previous anastomosis site in a patient with Crohn’s disease (H&E), inset: Higher magnification view of acellular mucin pool; D: Acellular mucin pool (triangle) at previous diverticular pouch in colonic diverticulitis (H&E).