Immunocytochemical localization of lymphatic and venous vessels in colonic polyps and adenomas

Histopathological localization of lymphatic vessels has been hindered because of a lack of suitable immunocytochemical markers for lymphatic vessels. Using lymphatic vessels endothelial hyaluronan receptor-1 (LYVE-1) immunocytochemical staining, hyperplastic polyps, tubular adenomas to villous adenomas, were investigated for lymphatic vessels compared with immunostained blood vessels using factor-8. Four cases each of hyperplastic polyps, tubular adenomas to villous adenomas, were routinely fixed in formalin and embedded in paraffin and were immunostained using goat anti-LYVE-1 for lymphatic vessels and rabbit anti-factor-8 for blood vessels. In normal colon and hyperplastic polyps, slender lymphatic vessels were noted in muscularis mucosa, which spread into the base of colonic crypt, whereas round venous vessels, they extend into lamina propria. In tubular adenomas, small lymphatic and venous vessels were noted in broad fibrous stalks. In villous adenomas, smaller lymphatic and venous vessels were noted in fine intervillous stroma. In normal colon and hyperplastic polyps, slender, irregularly shaped lymphatic vessels were present in muscularis mucosa, spreading into the base of the colonic crypt. In tubular adenomas, small lymphatic and venous vessels were noted in fibrous stalks. In villous adenomas, smaller lymphatic and venous vessels were noted in intervillous stroma. There are no increased lymphatic and venous vessels in intermucosal stroma and stalks of adenomas compared with normal colon.