title: Histological overlap between colorectal villous/tubulovillous and traditional serrated adenomas.
abstract: OBJECTIVE
  To ascertain the degree of histological overlap between conventional villous/tubulovillous (VA/TVAs) and traditional serrated adenomas (TSA).
  
  
  RESULTS
  A total of 180 polyps from the left colon/rectum diagnosed as VA/TVAs were retrieved randomly and reviewed by five pathologists looking specifically at luminal serration, cytoplasmic eosinophilia and the presence of ectopic crypt foci (ECF). For comparative purposes, 100 tubular adenomas and 80 TSAs were also examined. Twenty VA/TVAs were reclassified as TSA. Luminal serration as noted in TSA was not seen in any of the remaining 160 polyps, ECFs were noted in 55 of the 160 VA/TVAs (34%), while cytoplasmic eosinophilia (constituting <50% of the adenoma) was noted in only 10 of 160 cases (6.2%).
  
  
  CONCLUSIONS
  Ectopic crypt foci and cytoplasmic eosinophilia are encountered in sporadic VA/TVAs but not to the same extent and degree as in TSA. ECFs were found in one-third of cases, but cytoplasmic eosinophilia is rare. The pattern of luminal serration in TSA is very characteristic and not recapitulated in VA/TVA. The occurrence of all three histological features together occurs only in TSA. ECFs are not a sine qua non for TSA and are encountered commonly in VA/TVAs. VA/TVAs often contain occasional glands typical of TSA.
authors.affiliation: Department of Pathology, Laboratory Medicine Program, University Health Network and University of Toronto, Toronto, ON, Canada.
authors.forename: Sara
authors.initials: S
authors.lastname: Hafezi-Bakhtiari
authors.forename: Lai Mun
authors.initials: LM
authors.lastname: Wang
authors.forename: Richard
authors.initials: R
authors.lastname: Colling
authors.forename: Stefano
authors.initials: S
authors.lastname: Serra
authors.forename: Runjan
authors.initials: R
authors.lastname: Chetty
mesh_terms: D000236:Adenoma / Q000473:pathology*; D003111:Colonic Polyps / Q000473:pathology; D015179:Colorectal Neoplasms / Q000473:pathology*; D006801:Humans
keywords: adenoma; colon; ectopic crypt foci; overlap histology; serrated polyps; traditional serrated adenoma