Histopathological findings of a SNADET with the IP. a, b Histopathological pictures showing low-grade tubular adenoma. c, d The tumor contains goblet cells, Paneth cells, and brush border. e–h IHC for phenotypes shows negativity for MUC5AC (e) and MUC6 (f) and positivity for MUC2 (g) and CD10 (h), compatible with the intestinal mucin phenotype. SNADET, superficial non-ampullary duodenal epithelial tumor; IP, intestinal phenotype; IHC, immunohistochemistry.