Pathology of premalignant and malignant disease of the esophagus

Abstract

Like most structures of the alimentary canal, the esophagus is a tubular muscular structure that contains a mucosa, submucosa, muscularis propria, and surrounding connective tissue (termed adventitia in the esophagus) (Fig. 3.1). Anatomically, the esophagus extends from the cricopharyngeal muscle, which forms the upper esophageal sphincter, to the lower esophageal junction, where the stomach originates. Histologically, the mucosa consists of a stratifi ed non-keratinizing squamous epithelium, lamina propria, and muscularis mucosae. The squamous epithelium sits atop a basement membrane that separates it from the lamina propria. The lamina propria is composed of loose fi broconnective tissue, lymphatic spaces, and capillary vessels. The muscularismucosae is a thin muscular layer that separates the mucosa from the submucosa. The submucosa is composed of dense irregular fi brovascular connective tissue admixed withscattered mucin-producing glands (esophageal submucosal glands) and ducts, which aidinthe passage of food. Deep to the submucosa is the muscularis propria, which is primarily composed of striated muscle in the upper 1/3 of the esophagus, smooth muscle in the lower 1/3 of the esophagus, and a mixture of both in the mid esophagus. Finally, deep to the muscularis propria is the adventitia, a layer of connective tissue andadipose tissue that helps link the esophagus to adjacent structures. The esophagus, unlike most tubular structures of the alimentary canal, lacks a serosa.