Digging Deeper into Problematic Polyps: Incidence of Diagnostic Change in Colorectal Polyp Specimens after Deeper Sectioning at Two Different Laboratories
Jennifer A Nielsen, Donna J Lager, Matthew Lewin, James Weber, Cory A Roberts. ProPath, Dallas, TX; Texas Digestive Disease Consultants, Southlake, TX
Background: Clinically significant and completely benign polyps in colorectal (CR) biopsies are often asymptomatic and can be endoscopically homogenous. Among CR polyps, adenomas are of particular concern, because of their malignant potential and subsequent obligation for more extensive patient follow-up. Occasionally, endoscopically evident CR “polyps” are non-diagnostic (ND), and it is necessary to obtain deeper levels from the tissue block to improve diagnostic accuracy and provide the most effective patient treatment. The reported adenoma detection rates on deeper sectioning range from 1.29% to 19.7% of ND CR “polyps." This study sought to determine the rate of adenoma detection on deeper sectioning from two laboratories staffed by the same pathologists.
Design: After the initial assessment, three deeper levels were obtained in a total of 100 sequential ND CR polyps from each laboratory, and the change in diagnosis was recorded. All ND biopsies were grouped into one of three categories based on original observations: no histologic abnormality (NA), lymphoid aggregate(s) (LA), or suggestive of hyperplastic polyp(s) (SHPP). The diagnoses with respect to biopsy location (ascending, transverse, descending, or rectosigmoid colon) were tabulated. All original slides and corresponding deeper levels were blindly reviewed by a second pathologist to confirm both the original impression and final diagnosis.
Results: Of the 2853 CR “polyp” biopsies accessioned during the period of study, 12.4% were considered ND. Within the subset of 200 ND cases from both laboratories with deeper level sectioning, new diagnostic information was rendered in 43 (21.5%) and adenomas specifically in 16 (8.00%). Each laboratory had an identical adenoma conversation rate of 8%. There was no correlation between the biopsy location and adenoma detection on deeper sectioning. Biopsies that were originally NA were statistically more likely to uncover new diagnostic information than those with either LA or SHPP.
Conclusions: These results support the routine ordering deeper levels on ND CR polyps to improve adenoma detection rates, especially those cases without any histologic abnormality. The location of the biopsy within the colon cannot be used to predict adenoma conversion. Deeper levels should be performed on ND CR polyps when only one polyp is biopsied but may not alter clinical management if other adenomas are present.
Tuesday, March 5, 2013 1:00 PM
Poster Session IV # 122, Tuesday Afternoon