Pitfalls in gastrointestinal tract haematopoietic lesions.

Specimens from the gastrointestinal (GI) tract are among the most commonly encountered in routine pathology practice worldwide. It is well known that the luminal GI tract is home to various areas rich in mucosa-associated lymphoid tissue (MALT), whether native or acquired. The latter may be particularly problematic due to its well-known predisposing factors such as Helicobacter pylori infection and autoimmune conditions. Nevertheless, native GI structures are often the subject of query, particularly in conditions that may mimic lymphoproliferative conditions, including infectious and inflammatory diseases. Herein, we describe and share common clinicopathological findings in our daily practice that are challenging to distinguish from subtle low-grade neoplastic lymphoproliferative disorders.

Histologic Study of the Esophagogastric Junction of Organ Donors Reveals Novel Glandular Structures in Normal Esophageal and Gastric Mucosae.

INTRODUCTION: Whether cardiac mucosa at the esophagogastric junction is normal or metaplastic is controversial. Studies attempting to resolve this issue have been limited by the use of superficial pinch biopsies, abnormal esophagi resected typically because of cancer, or autopsy specimens in which tissue autolysis in the stomach obscures histologic findings. METHODS: We performed histologic and immunohistochemical studies of the freshly fixed esophagus and stomach resected from 7 heart-beating, deceased organ donors with no history of esophageal or gastric disease and with minimal or no histologic evidence of esophagitis and gastritis. RESULTS: All subjects had cardiac mucosa, consisting of a mixture of mucous and oxyntic glands with surface foveolar epithelium, at the esophagogastric junction. All also had unique structures we termed compact mucous glands (CMG), which were histologically and immunohistochemically identical to the mucous glands of cardiac mucosa, under esophageal squamous epithelium and, hitherto undescribed, in uninflamed oxyntic mucosa throughout the gastric fundus. DISCUSSION: These findings support cardiac mucosa as a normal anatomic structure and do not support the hypothesis that cardiac mucosa is always metaplastic. However, they do support our novel hypothesis that in the setting of reflux esophagitis, reflux-induced damage to squamous epithelium exposes underlying CMG (which are likely more resistant to acid-peptic damage than squamous epithelium), and proliferation of these CMG as part of a wound-healing process to repair the acid-peptic damage could result in their expansion to the mucosal surface to be recognized as cardiac mucosa of a columnar-lined esophagus.

Comparison of esophageal submucosal glands in experimental models for esophagus tissue engineering applications.

OBJECTIVE: Esophagus tissue engineering holds promises to overcome the limitations of the presently employed esophageal replacement procedures. This study investigated 5 animal models for esophageal submucosal glands (ESMG) to identify models appropriate for regenerative medicine applications. Furthermore, this study aimed to measure geometric parameters of ESMG that could be utilized for fabrication of ESMG-specific scaffolds for esophagus tissue engineering applications. METHODS: Ovine, avian, bovine, murine, and porcine esophagus were investigated using Hematoxylin-Eosin (HE), Periodic Acid Schiff (PAS), and Alcian Blue (AB), with AB applied in 3 pH levels (0.2, 1.0, and 2.5) to detect sulphated mucous. Celleye® (version F) was employed to gain parametric data on ESMGs (size, perimeter, distance to lumen, and acini concentration) necessary for scaffold fabrication. RESULTS: Murine, bovine, and ovine esophagus were devoid of ESMG. Avian esophagus demonstrated sulphated acid mucous producing ESMGs with a holocrine secretion pattern, whereas sulphated acid and neutral mucous producing ESMGs with a merocrine secretion pattern were observed in porcine esophagus. Distance of ESMGs to lumen ranged from 127-340 µm (avian) to 916-983 µm (porcine). ESMGs comprised 35% (avian) to 45% (porcine) area of the submucosa. ESMG had an area of 125000 µm2 (avian) to 580000 µm2 (porcine). CONCLUSION: Avian and porcine esophagus possesses ESMGs. However, porcine esophagus correlates with data available on human ESMGs. Geometric and parametric data obtained from ESMG are valuable for the fabrication of ESMG-specific scaffolds for esophagus tissue engineering using the hybrid construct approach.

The Esophageal Epithelial Barrier in Health and Disease.

Dysfunction in the esophageal epithelial barrier function is a major source for morbidity. To better understand the pathophysiologic pathways of the diseases associated with barrier dysfunction, including gastroesophageal reflux disease, eosinophilic esophagitis, Barrett's esophagus, and obesity, it is important to understand the esophageal epithelial embryologic development, microscopic anatomy with a special focus on the barrier structure and function, extraepithelial defense mechanisms, and how these change in the diseased state. In recent years, significant progress has been made in elucidating the esophageal barrier structure and function both in vitro and in vivo. This has enhanced the understanding of mechanisms of disease, and may also allow identification of therapeutic targets that can help in the management of these diseases. This review provides a detailed discussion regarding the esophageal epithelial barrier structure and function, the current and historical techniques used to study the barrier, and how it is affected by common esophageal diseases.