The normal configuration and interindividual differences in intramural lymphatic vessels of the esophagus

Abstract

Recently, interindividual differences in lymphatic vessel density among patients with cancer have become a focus of interest for surgeons as a significant prognostic factor. Little morphometric information is available about esophageal lymphatics in the absence of esophageal pathologic changes. We used D2-40 immunohistochemical examination to clarify the normal configuration of the esophageal intramural lymphatics and to evaluate morphometrically preexisting mucosal vessels. D2-40 immunohistochemical staining for human lymphatic epithelium was performed at three sites in the cervical and thoracic esophagus in 16 donated cadavers without macroscopic malignancy or chronic inflammation. We determined the total numbers of lymphatic vessels and their complete circumferential lengths. Our immunohistochemical evaluation consistently demonstrated mucosal longitudinal and intermuscular circumferential vessels. In contrast to a previous diagram, the submucosal lymphatics were limited to a few circumferential and marginal vessels. On the basis of these findings, we suggest a new scheme for the intramural lymphatic vessels. In this morphometric study, interindividual differences in number and circumferential length of mucosal lymphatic vessels ranged from 100% to 200% (2-3 times), and site-dependent differences were not evident. After correction for esophageal thickness, interindividual differences in lymphatic vessel density were still 2-fold. We hypothesized that the greater length and number of lymphatic vessels in the lamina propria mucosae are likely to provide greater opportunity for lymphatic vessel invasion of cancer. Thus propensity toward cancer invasion would seem to depend not only on cancer pathology but also on individual anatomic features.