Traditional serrated adenoma: an update

Hum Pathol. 2015 Jul;46(7):933-8. doi: 10.1016/j.humpath.2015.04.002. Epub 2015 Apr 20.


Although recognized 25 years ago, the traditional serrated adenoma (TSA) remains an ongoing source of diagnostic and biologic debate. Recent research has greatly improved our understanding of the morphological and molecular aspects of these polyps. In particular, the recognition of ectopic crypt foci (ECFs) in combination with typical cytology and slitlike serrations improves diagnostic reproducibility. Awareness that many TSAs, particularly BRAF-mutated TSAs, arise in precursor microvesicular hyperplastic polyps and sessile serrated adenomas can aid in making this diagnosis and should not be confused with a sessile serrated adenoma with dysplasia. At a molecular level, TSAs can be divided into 2 groups based on their BRAF or KRAS mutation status. The development of overt cytologic dysplasia is accompanied by TP53 mutation, Wnt pathway activation, and, in some cases, silencing of CDKN2A. Importantly, however, mismatch repair enzyme function is retained. Thus, the TSA is an important precursor of aggressive molecular subtypes of colorectal carcinoma.

Keywords: BRAF; CIMP; KRAS; Serrated polyp; Traditional serrated adenoma.

Publication types

  • Review

MeSH terms

  • Adenomatous Polyps* / classification
  • Adenomatous Polyps* / genetics
  • Adenomatous Polyps* / metabolism
  • Adenomatous Polyps* / pathology
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Biopsy
  • Colonic Polyps* / classification
  • Colonic Polyps* / genetics
  • Colonic Polyps* / metabolism
  • Colonic Polyps* / pathology
  • Colonoscopy
  • Colorectal Neoplasms* / classification
  • Colorectal Neoplasms* / genetics
  • Colorectal Neoplasms* / metabolism
  • Colorectal Neoplasms* / pathology
  • DNA Mutational Analysis
  • Diagnosis, Differential
  • Gene Expression Regulation, Neoplastic
  • Genetic Predisposition to Disease
  • Humans
  • Immunohistochemistry
  • Mutation
  • Phenotype
  • Predictive Value of Tests
  • Prognosis
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins B-raf / genetics
  • Proto-Oncogene Proteins p21(ras)
  • Signal Transduction
  • Tumor Suppressor Protein p53 / genetics
  • ras Proteins / genetics


  • Biomarkers, Tumor
  • KRAS protein, human
  • Proto-Oncogene Proteins
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • Proto-Oncogene Proteins p21(ras)
  • ras Proteins