Utility of MIB-1 (Ki-67) in evaluating diminutive colorectal polyps with cautery artifact.
BACKGROUND
Accurate interpretation of colorectal polyp histology is essential in the decision-making process during treatment and surveillance following polypectomies. However, interpretation of diminutive colorectal polyps removed by thermal electrocoagulation (hot biopsy technique) is often problematic as a result of cautery artifact.


OBJECTIVE
To evaluated the usefulness of the proliferation marker MIB-1 (Ki-67) as an aid in the differential diagnosis of diminutive colorectal polyps with cautery artifact, as adenomatous and nonadenomatous polyps display different patterns of epithelial proliferation.


METHODS
Seventy-five diminutive colorectal polyps with extensive cautery artifact displaying at least the upper portions of 3 adjacent crypts with the corresponding surface epithelium were evaluated and immunolabeled with MIB-1. They included 25 cases in which a definitive or presumptive diagnosis could not be reached (indeterminate polyps), 25 cases diagnosed as compatible with adenomatous polyp, and 25 cases diagnosed as compatible with nonadenomatous polyp.


RESULTS
MIB-1 immunoreactivity was well preserved in the cauterized areas. Among indeterminate polyps, MIB-1 stained upper crypts and surface epithelium in 14 cases (adenomatous polyp staining pattern) and revealed minimal or absent staining in these areas in 11 cases (nonadenomatous polyp staining pattern). All cases diagnosed as compatible with adenomatous polyp displayed the adenomatous polyp staining pattern. In contrast, all cases diagnosed as compatible with nonadenomatous polyp revealed the nonadenomatous polyp staining pattern.


CONCLUSIONS
Immunoreactivity for MIB-1 may be used as a beneficial adjunctive test to help diagnose diminutive colorectal polyps with extensive cautery artifact.
Groisman
Gabriel M
GM
Department of Pathology, Hillel Yaffe Medical Center, Hadera 38100, Israel. groisman@hy.health.gov.il
Amar
Mary
M
Meir
Alona
A
D018256:Adenomatous Polyps / Q000175:diagnosis*; D000368:Aged; D016477:Artifacts; D002425:Cautery; D003111:Colonic Polyps / Q000175:diagnosis*; D003113:Colonoscopy; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007417:Intestinal Polyps / Q000175:diagnosis*; D019394:Ki-67 Antigen / Q000032:analysis*; D008297:Male; D012002:Rectal Diseases / Q000175:diagnosis*
D019394:Ki-67 Antigen