Ectopic crypt foci in conventional and serrated colorectal polyps.
OBJECTIVE
Despite almost pathognomonic status of ectopic crypt foci (ECF) in the diagnosis of traditional serrated adenoma (TSA), there are few systematic studies on their prevalence in other types of colon polyps or in adenomas adjacent to colorectal cancer (CRC).


METHODS
We calculated ECF in all the polyps (n=922) removed in the colonoscopy in Oulu University Hospital in 2001. Moreover, to study ECF in precursor lesions next to CRCs, we re-examined a previously described cohort of 148 CRCs.


RESULTS
ECF were seen in 53 (5.7%) polyps representing 28 (6.5%) tubular adenomas (TAs), 14 (53.8%) tubulovillous adenomas (TVAs), 2 (100.0%) villous adenomas (VAs) and 9 (100.0%) TSAs. In all TSAs and VAs, the density of ECF was higher than in TVAs and TAs. An adjacent precursor lesion was recognised in 28 of 148 (18.9%) CRCs. Twenty-four (85.7%) of these contained ECF.


CONCLUSIONS
ECF can most frequently be observed in TSAs but also in many TVAs, VAs and TAs, reflecting a histological overlap between serrated and conventional polyps. Especially, precursor lesions adjacent to CRC frequently contain ECF.
Cancer and Translational Medicine Research Unit, University of Oulu, Oulu, Finland.|Oulu University Hospital and Medical Research Center Oulu, Oulu, Finland.
Sara A
SA
Väyrynen
Cancer and Translational Medicine Research Unit, University of Oulu, Oulu, Finland.|Oulu University Hospital and Medical Research Center Oulu, Oulu, Finland.
Juha P
JP
Väyrynen
Oulu University Hospital and Medical Research Center Oulu, Oulu, Finland.|Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu, Oulu, Finland.
Kai
K
Klintrup
Oulu University Hospital and Medical Research Center Oulu, Oulu, Finland.|Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu, Oulu, Finland.
Jyrki
J
Mäkelä
Cancer and Translational Medicine Research Unit, University of Oulu, Oulu, Finland.|Oulu University Hospital and Medical Research Center Oulu, Oulu, Finland.
Anne
A
Tuomisto
Cancer and Translational Medicine Research Unit, University of Oulu, Oulu, Finland.|Oulu University Hospital and Medical Research Center Oulu, Oulu, Finland.
Markus J
MJ
Mäkinen
D000236:Adenoma / Q000145:classification*; D018253:Adenoma, Villous / Q000145:classification*; D000368:Aged; D000369:Aged, 80 and over; D003106:Colon / Q000473:pathology; D003110:Colonic Neoplasms / Q000145:classification*; D003111:Colonic Polyps / Q000145:classification* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000145:classification*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged
COLORECTAL CANCER; HISTOPATHOLOGY; IMMUNOHISTOCHEMISTRY