Exploring the mesenteric lymphatic apparatus: A morphological and immunohistochemical investigation with clinical correlations.

Modern immunohistochemical techniques allow a detailed study of the lymphatic system in many organs and areas of the body. We performed an in-depth study on lymphatic vessels of the ileal and colonic mesenteries, together with the greater omentum where they appear particularly numerous and mainly represented by capillaries interconnected among themselves and with lymph nodes. The capillary wall consists of a fine single sheath of endothelial cells wrapped around by a subtle collagen membrane and deprived of valves. The progression of lymph flow is promoted by external forces acting on the capillary walls. Only at the mesenteric roots can pre- and post-lymph nodal collector vessels be observed. Our observations help to explain different patho-physiological correlations and the possible presence of skip lymph node metastases.