Identification of lymphatic vessels in malignant, adenomatous and normal colonic mucosa using the novel immunostain D2-40.

Distribution of lymphatic vessels in normal and neoplastic colon has been previously analyzed with electron microscopic techniques, as reliable antibodies have not been available for selective lymph vessel staining. A novel monoclonal antibody, D2-40, is recently available to differentiate lymphatic vessels from blood vessels. In this study, we analyzed the distribution of lymphatic vessels in normal colon, adenomas with and without superficial stalk invasion and invasive carcinomas without identifiable polypoid precursor lesions. In contrast to previous studies, we found lymphatic vessels in superficially misplaced stalk stroma in adenomas, and closely associated with early invasive epithelial nests in invasive lesions. Lymphatic vessels were identified within the lamina propria of the in situ aspect of in invasive tumors. We conclude that lymphatic vessel structures are seen more superficially in adenomas and invasive carcinomas than previously described. Since intramucosal carcinomas in adenomas do not metastasize, these lymph vessels may be immature or not communicate with deeper lymphatics. Proliferation and distribution of lymphatic vessels may be related to prognosis and early metastasis.