Lymphangioma of large intestine: report of ten cases with endoscopic and pathologic correlation

Background: Lymphangioma of the intestinal tracts is extremely rare and usually presents as a sessile or pedunculated polyp. The cause of these gross morphologic differences is unknown. The aim of this study was to investigate the characteristic histopathology of the colonic lymphangiomas in comparison with their endoscopic findings. Methods: Ten colonic lymphangiomas, diagnosed and resected endoscopically between 1992 and 1999, were microscopically examined and immunohistochemically stained with CD31, CD34, Factor VIII-related antigen, and smooth muscle actin. Results: The characteristic endoscopic finding was a transparent, fluctuating sessile (7 cases) or pedunculated (3 cases) polypoid mass with the color of normal colonic mucosa. Proliferative and dilated lymphatic tumor vessels were found in the colonic mucosa as well as in the submucosa in seven cases. In three pedunculated lymphangiomas, dilated lymphatics were exclusively restricted to the submucosa. The endothelial lining cells stained positively for both CD31 and Factor VIII-related antigen in all 10 cases tested, but most cases were negative for CD34. Conclusion: A pedicle does not exclude the endoscopic diagnosis of lymphangioma and there is a close correlation between its presence and histologic submucosal localization of dilated lymphatic vessels.