Hyperplastic/serrated polyposis in inflammatory bowel disease: a case series of a previously undescribed entity

Am J Surg Pathol. 2008 Feb;32(2):296-303. doi: 10.1097/PAS.0b013e318150d51b.


Herein, we describe the clinical, pathologic, immunohistochemical, and molecular features of 3 unique patients with long standing inflammatory bowel disease, all of whom developed numerous discrete hyperplastic/serrated colonic polyps similar to those described in the hyperplastic/serrated polyposis syndrome. The 3 patients (2 with ulcerative colitis and 1 with Crohn ileo-colitis) were evaluated for a variety of clinical, histologic (including the type, location and number of polyps in the colon), and immunohistochemical features [MLH-1, MSH-2, MGMT (O(6)-methylguanine-DNA methyltransferase), beta-catenin, and p53]. KRAS and BRAF mutation analysis was also performed on a subset of polyps from 2 patients. All patients had moderate-severe pancolitis of more than 10 years duration and had >20 colonic polyps. None had polyps in the upper gastrointestinal tract. Pathologically, a combination of conventional hyperplastic polyps and sessile serrated polyps (adenomas) were present in the 3 cases. In addition, serrated adenomas were present in 2 and conventional adenomas in 1. Two patients also had synchronous adenocarcinoma. All 3 cases showed retention of MLH-1 and MSH-2, and a membranous beta-catenin staining pattern. However, 2 cases showed loss of MGMT in several serrated polyps, and one also in adjacent colitic mucosa. KRAS mutations were detected in 5/11 serrated polyps. However, BRAF mutations were not present in any of the polyps tested. These findings suggest the possibility of a serrated pathway of carcinogenesis in inflammatory bowel disease characterized by silencing of MGMT, most likely by gene promoter methylation, KRAS mutations, and possibly other, as yet, uncharacterized molecular alterations, resulting eventually in progression to adenocarcinoma.

Publication types

  • Case Reports

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Adenocarcinoma / genetics
  • Adenocarcinoma / metabolism
  • Adenocarcinoma / pathology
  • Adenomatous Polyps / genetics
  • Adenomatous Polyps / metabolism
  • Adenomatous Polyps / pathology*
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Colonic Neoplasms / genetics
  • Colonic Neoplasms / metabolism
  • Colonic Neoplasms / pathology*
  • Colonic Polyps / genetics
  • Colonic Polyps / metabolism
  • Colonic Polyps / pathology*
  • Female
  • Humans
  • Hyperplasia
  • Inflammatory Bowel Diseases / genetics
  • Inflammatory Bowel Diseases / metabolism
  • Inflammatory Bowel Diseases / pathology*
  • Male
  • Middle Aged
  • MutL Protein Homolog 1
  • MutL Proteins
  • Mutation
  • Neoplasm Proteins / metabolism
  • Nuclear Proteins / metabolism
  • Precancerous Conditions / genetics
  • Precancerous Conditions / metabolism
  • Precancerous Conditions / pathology*
  • Proto-Oncogene Proteins B-raf / genetics
  • Proto-Oncogene Proteins B-raf / metabolism
  • Syndrome


  • Adaptor Proteins, Signal Transducing
  • Biomarkers, Tumor
  • MLH1 protein, human
  • Neoplasm Proteins
  • Nuclear Proteins
  • PMS1 protein, human
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • MutL Protein Homolog 1
  • MutL Proteins