title: Colorectal polyps with extensive absorptive enterocyte differentiation: histologically distinct variant of hyperplastic polyps.
abstract: BACKGROUND
  The histologic classification of colorectal polyps is well established. However, practicing pathologists may still occasionally encounter colorectal polyps that are difficult to classify. We studied 6 colorectal polyps that showed uncommon histologic features that have not been described in the English language literature.
  
  
  METHODS
  The polyps were studied using standard hematoxylin-eosin stain, mucin histochemistry, and electron microscopy.
  
  
  RESULTS
  The 6 polyps we studied showed extensive papillary and villous structures with alternating villi and crypts. The villi were lined by well-differentiated absorptive cells, whereas the crypts were lined by immature glandular cells, thus mimicking the histology of the small intestinal mucosa.
  
  
  CONCLUSIONS
  These polyps appear to represent a variant of the hyperplastic polyp, in as much as cellular maturation (immature glandular cells differentiate into the mature surface absorptive cells) is the essential feature distinguishing hyperplastic polyps from adenomas.
authors.affiliation: Department of Pathology, Northwestern Memorial Hospital, Chicago, Ill 60611, USA.
authors.forename: H
authors.initials: H
authors.lastname: Yokoo
authors.forename: I
authors.initials: I
authors.lastname: Usman
authors.forename: S
authors.initials: S
authors.lastname: Wheaton
authors.forename: P A
authors.initials: PA
authors.lastname: Kampmeier
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003111:Colonic Polyps / Q000473:pathology* / Q000648:ultrastructure; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000648:ultrastructure; D006801:Humans; D008297:Male; D008854:Microscopy, Electron