Identification of histologically distinct conventional adenomas that arise predominately in patients with sessile serrated adenomas

Rish K. Pai, Alexander Craig MacKinnon, Loren Joseph, Amy Noffsinger, John Hart

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


We have recently shown that a study population of patients with at least 1 sessile serrated adenoma (SSA) are 4 times more likely to harbor synchronous serrated polyps [SSAs, traditional serrated adenomas (TSAs) and right sided hyperplastic polyps] than a unselected population of patients. However, 35% of the polyps in the study patients were conventional adenomas (CAds). We hypothesized that the CAds in these study patients would have histologic and molecular differences compared with CAds from a control population without sessile serrated adenomas. To this end, 104 study and 79 control CAds were analyzed according to 9 histologic criteria. A subset of these polyps was also screened for BRAF mutations, KRAS mutations, CpG island methylation, and MUC6 expression. A total of 31 study CAds and 2 control CAds had atypical histologic features (bright cytoplasmic eosinophilia ± focal serrations and crypt dilatation). None of the adenomas tested had mutations in BRAF or KRAS. Evidence of low levels of CpG island methylation was seen in 35% of the atypical CAds and in only 4.5% of the typical CAds. In addition, these atypical CAds were more likely to express MUC6. Thus, the presence of cytoplasmic eosinophilia with or without focal serrations and crypt dilatation identifies a subset of CAds with characteristics of the serrated neoplasia pathway. These atypical CAds occur more commonly in patients predisposed to developing SSAs and suggest the presence of a mucosal field defect in these patients.

Original languageEnglish (US)
Pages (from-to)355-363
Number of pages9
JournalAmerican Journal of Surgical Pathology
Issue number3
StatePublished - Mar 2010


  • CIMP
  • Colorectal cancer
  • Conventional adenoma
  • CpG island methylation
  • Hyperplastic polyp
  • Hyperplastic polyposis syndrome
  • Microsatellite instability
  • Sessile serrated adenoma
  • Sessile serrated polyp
  • Traditional serrated adenoma
  • Tubular adenoma

ASJC Scopus subject areas

  • Anatomy
  • Surgery
  • Pathology and Forensic Medicine


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