Читать книгу Gastrointestinal Pathology - Группа авторов - Страница 39

The esophageal mucosa is composed of a non‐keratinizing flat stratified squamous epithelium, lamina propria, and muscularis mucosae (Figure 2.2; Table 2.1). The squamous epithelium is 10–20 cell layers thick measuring 300–500 μm in thickness. The prickle cells contain a large quantity of cytoplasmic glycogen, which stains positively with periodic acid–Schiff (PAS). The basal proliferative zone, the cuboidal or polyhedral basal and parabasal cells account for 15% or less of the epithelial thickness. A small number of specialized cell types, including T lymphocytes, Langerhans cells, endocrine cells, and melanocytes are also present in the deep/parabasal epithelium. The lamina propria consists of loose connective tissue with scattered inflammatory cells, vessels, nerves, and small mucous glands. The lamina propria papillae normally extend into the epithelium for 1/3–1/2 of its thickness. The muscularis mucosae is a thick layer of smooth muscle bundles oriented longitudinally. In the distal 1–2 cm of the esophagus, the basal zone, papillae, and intraepithelial cells may be more prominent, and include rare eosinophils. Esophageal mucosal biopsies typically include the squamous epithelium and scant lamina propria. The muscularis mucosae is seldom present, and better identified in esophageal mucosal resection specimens.