An immunohistochemical and stereological appraisal of mesocolic lymphangiologyimplications for surgical technique in resectional colorectal surgery

Background: Inadequate mesenteric resection is associated with adverse oncologic outcome in colon cancer, disruption of the mesenteric lymphatic package has been implicated.. Recent studies have determined mesenteric anatomy and histology and now provide an opportunity to accurately determine the distribution of lymphatic vessels(LV). The aim of this study was to characterise the distribution of the LV within the small intestinal and colonic mesentery, and in Toldts fascia. Methods: Mesenteric samples were harvested from 12 human cadavers. Samples were taken from the small bowel mesentery, ascending, transverse, descending mesocolon and from both apposed and non-apposed mesosigmoid. Serial sections were stained immunohistochemically with monoclonal antibody D2-40 (podoplanin), and Massons Trichrome. Lymphatic vessel (LV) density and radius of diffusion were determined using a stereological approach. Results: LV were embedded within the mesenteric connective tissue lattice throughout each region. LV were identifiable within the submesothelial connective tissue. Along the upper submesothelial layer they measured 10.2 ± 4.1 lm in diameter, and had an average radius of diffusion of 174.72 ± 97.68 lm. Unexpectedly, LV were identified in Toldts fascia where they measured 4.3 ± 3.1 lm in diameter, and had a radius of diffusion of 165.12 ± 66.26 lm. Conclusions: This is the first study to systematically determine and quantify the distribution of lymphatic vessels within the mesenteric organ and underlying Toldts fascia. A rich lymphatic network occupies all levels of the mesenteric connective tissue lattice. Within the latter, they are found within 0.1 mm of peritonealised mesenteric surfaces and are separated by an averag