Vascular and lymphatic properties of the superficial and deep lamina propria in Barrett esophagus

A well-known type of mesenchymal/epithelial interaction occurs in Barrett esophagus (BE) characterized by the formation of a new, superficially located, muscularis mucosae (MM), which results in the division of the lamina propria (LP) into a superficial and deep compartment. The vascular and lymphatic properties of these 2 regions of LP are unknown. The risk of metastases of carcinomas that infiltrate these 2 anatomic areas also remains unclear. The aim of this study was to evaluate the density of blood vessels and lymphatic spaces within the superficial and deep LP and submucosa in patients with BE, and to compare the results to normal squamous-lined esophagus. Thirty esophago-gastrectomy specimens were stained immunohistochemically with CD31 (stains blood vessel and lymphatic endothelium) and D2-40 (stains lymphatic endothelium only). The density of CD31(+) blood and lymphatic vessels (per 20 x field) in BE (superficial LP = 37 and deep LP = 38) was significantly lower compared with the LP of squamous-lined esophagus (68; P < 0.001). However, the total number of blood and lymphatic vessels in the superficial and deep LP in BE was statistically similar to the LP of squamous-lined esophagus. The density of CD31(+) blood and lymphatic vessels (per 20 x field) in the submucosa of BE (21) was not significantly different from the submucosa of squamous-lined esophagus (23; P > 0.05). We conclude that in BE, the "native" LP in squamous-lined esophagus is separated into 2 LP compartments (superficial and deep) by the formation of a new MM. These findings suggest that carcinomas that invade through the superficial MM into the deep LP should be considered "intramucosal" rather than "submucosal." Further outcome studies are needed to evaluate the risk of vascular/lymphatic metastasis in BE patients with different levels of LP invasion.