Pedunculated serrated polyp with histologic features of sessile serrated adenoma: a clinicopathologic and molecular study

Am J Surg Pathol. 2013 Jul;37(7):1039-43. doi: 10.1097/PAS.0b013e3182805696.

Abstract

In this study, we describe a previously undescribed pedunculated serrated polyp of the colon showing typical features of sessile serrated adenoma/polyp (SSA/P). All polyps were pedunculated, located in the proximal colon, small in size, and occurred in elderly patients. Histologically, the polyps showed typical features of SSA/P in the basal crypts with irregular, asymmetric expression of Ki-67. All polyps showed the BRAF-V600E mutation. The cells in the polyps did not show obvious cytologic dysplasia, prominent serration, or diffuse cytoplasmic eosinophilia with any occurrence of the so-called "ectopic crypt formation." We consider pedunculated serrated polyp showing features of SSA/P as a previously undescribed form of serrated adenoma/polyp in the spectrum of serrated neoplasia, which might represent a pedunculated variant of SSA/P or a precursor lesion of proximally located traditional serrated adenomas in the earliest stage.

MeSH terms

  • Adenoma / genetics
  • Adenoma / metabolism
  • Adenoma / pathology*
  • Aged
  • Biomarkers, Tumor / metabolism
  • Colon
  • Colonic Neoplasms
  • Colonic Polyps / genetics
  • Colonic Polyps / metabolism
  • Colonic Polyps / pathology*
  • Female
  • Humans
  • Ki-67 Antigen / metabolism
  • Male
  • Middle Aged
  • Molecular Diagnostic Techniques
  • Mutation
  • Precancerous Conditions / genetics
  • Precancerous Conditions / metabolism
  • Precancerous Conditions / pathology*
  • Proto-Oncogene Proteins B-raf / genetics
  • Retrospective Studies

Substances

  • Biomarkers, Tumor
  • Ki-67 Antigen
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf