Abstract
Introduction:We evaluated the effectiveness of D2-40 immunohistochemistry for detecting lymphatic invasion, in colonic adenocarcinoma with submucosal invasion removed under colonoscopy. Materials and Methods: Subjects were 30 cases of invasive colonic adenocarcinoma removed endoscopically and proven to have submucosal invasion. Serial paraffin sections were stained with hematoxylin-eosin (HE) or immunostained with D2-40, and the degree of lymphatic invasion was evaluated based on staining. Results: The number of lymphatic invasions was 2 lesions in 2 cases or 6 lesions in 5 cases by HE-stained or D2-40-immunostained sections. One lesion was detected by both HE and D2-40 antibody. The discrepancy in the degree of lymphatic invasion evaluated by HE or D2-40 was noted in 6 lesions in 5 cases. Underestimation in HE-stain-based evaluation compared to that in D2-40 was seen in 5 lesions among 4 cases. These were caused by obscure separation artifact, characteristic of lymphatic invasion, and the small size of lymphatic invasion. Overevaluation in HE-stained sections was noted in one lesion in 1 case, where D2-40 was unstained. Nonspecific D2-40 staining was often observed in tumor parenchyma, including structures just around the edge of tumor cell nests: this should not be confused with true lymphatic invasion. Conclusions: D2-40 is useful for accurately evaluating lymphatic invasion in colonic cancer with submucosal invasion undergoing colonoscopic resection.
