Vascular gastropathies

Gastric vascular gastropathies comprise a heterogeneous group of conditions characterized by alterations in the gastric circulation and their effects on the gastric mucosa. The best-defined conditions, from morphologic and pathogenetic viewpoints, are the watermelon stomach, which is described, and portal hypertensive gastropathy.

Portal Hypertensive Gastropathy

Clinical Manifestations and Pathogenesis Portal hypertensive gastropathy is a dilation of the mucosal vessels, more prominent in the proximal stomach, that occurs in a proportion of patients with cirrhosis of the liver; its prevalence parallels the severity of portal hypertension. Bleeding from this lesion is relatively uncommon and rarely severe; in general, patients with the most severe portal hypertension have diffuse lesions and higher rates of gastric bleeding.

Endoscopic Appearance The endoscopic appearance of portal hypertensive gastropathy is nonspecific and does not correlate well with the degree of portal hypertension. The endoscopic patterns have been variously described as snake skin, scarlatina rash, cherry-red spots, and mosaic. The mosaic pattern was found by a consensus conference to be the most reliable indicator of mild portal hypertensive gastropathy with a low risk of hemorrhage. Red marks suggest a more severe degree of hypertension and a greater risk of hemorrhage.

Histopathology Dilation and tortuosity of small arteries and veins, with occasional thickening of the walls, are among the pathological changes of portal hypertensive gastropathy. The changes are more prominent in the corpus and are more apparent in submucosal vessels than in mucosal capillaries. Because of the location of these changes and the understandable reluctance of most gastroenterologists to obtain large and deep biopsy samples from patients who may have an increased risk of bleeding, the diagnosis of portal hypertensive gastropathy is not commonly reached by evaluating mucosal biopsies. In patients with concurrent H.pylori gastritis, it is difficult, if not impossible, to separate the respective contribution of infection and congestion to the resulting complex of changes observed in the mucosa.

Management Because bleeding is relatively uncommon, most pati­ents do no require specific therapy. Sclerotherapy of esophageal varices does not seem to influence the natural history of this condition. In severe cases, portal decompression surgery, but not transjugular intrahepatic portosystemic shunting, is effective in reducing the risk of hemorrhage.

Hypertrophic gastropathies

In numerous inflammatory and noninflammatory conditions, the mucosal folds ( rugae) that confer a rugged appearance to the normal gastric corpus may become extremely enlarged and may give the mucosa an appearance that has been compared to that of the cerebral cortex (cerebriform). Based on this macroscopic morphologic characteristic, shared in various degrees by all of them, certain etiologically heterogeneous conditions have been categorized as hypertrophic gastritis, hypertrophic gastropathy, or, more recently, giant-fold gastropathies. To complicate our understanding of these diverse conditions further, many authors have used indiscriminately the term Ménétrier disease, after the condition described in 1888 by the French gastroenterologist who initially called it polyadenomes en nappe (polyps in layers).

In 1973, Ming introduced the term hyperplastic gastropathies and proposed a classification that recognizes three main histological types:

1. Foveolar hyperplasia, with normal or atrophic oxyntic glands and corresponding to Ménétrier’s description

2. Hyperplasia of oxyntic glands, with a largely unaffected mucous component and corresponding to Zollinger-Ellison syndrome

3. A mixed type, in which both mucous and oxyntic glands show variable degrees of hyperplasia; it incorporates various conditions that may cause mixed glandular hyperplasia, including infections ( H.pylori infection, CMV infection in children, syphilis, and histoplasmosis) and other diseases of uncertain origin (lymphocytic gastritis, eosino­philic gastroenteritis, sarcoidosis, and Cronkhite-Canada syndrome).

Ménétrier Disease

Ménétrier, in his original description, included patients with multiple hyperplastic polyps and patients with giant folds and focused his observa­tions on the increased gastric cancer risk of these patients. Today, the condition associated with his eponym is defined as an idiopathic diffuse enlargement of the gastric folds in the antrum. Histologically, glands show massive foveolar cell hyperplasia with normal or slightly reduced numbers of parietal and chief cells. Neither significant inflammatory infiltrates in the lamina propria nor epithelial lesions (erosions, intestinal metaplasia, or cellular atypia) are present. If chronic active inflammation or lymphocytic infiltration of the epithelium is seen, the large-fold type of H.pylori gastritis or lymphocytic gastritis should be considered. In children, giant folds are almost always associated with CMV infection. This association has rarely been reported in adults. The hyperplastic foveolar cells secrete large amounts of mucus and fluid resulting in protein-losing enteropathy (found in almost all patients) and hypoacidity (in part from dilution of the acid produced by oxyntic cells).

Pure Ménétrier disease is a rare condition, with an estimated prevalence of no more than 300 or 400 persons worldwide. Patients are more often men in their fifth or sixth decade who present with dramatic weight loss, epigastric and abdominal pain, nausea, and vomiting. Later in the course of the disease, usually protracted for several years and even decades, virtually all patients develop hypoalbuminemia as a consequence of the protein-losing enteropathy. The pathogenesis is unknown, but an interesting hypothesis has been put forward. Transforming growth factor-a (TGF-a), a critical mediator of gastric mucosal homeostasis normally produced by the gastric mucosa, inhibits acid secretion, stimulates mucosal repair, cell migration, and proliferation, and augments gastric mucin levels Overproduction of TGF-a could explain several of the disturbances occur­ring in Ménétrier disease. Support for this hypothesis is further lent by the successful treatment of some patients by a monoclonal antibody against the TGF-a receptor (the epidermal growth factor receptor). Other forms of treatment, including antacids, anticholinergic drugs, corticosteroids, H 2-receptor antagonists, and proton pump inhibitors, have been proven consistently ineffective. Eradication of H.pylori has been reported to have successfully cured patients with Ménétrier disease. One of the possible pathological aspects of H.pylori gastritis is the development of large, edematous folds, and this variant may have been interpreted as a type of H.pylori–induced Ménétrier disease. Not surprisingly, it regresses after the eradication of H.pylori infection.