Eosinophilic gastroenteritis. Immunohistochemical evidence for IgE mast cell-mediated allergy.

A surgical case of a middle-aged Japanese with eosinophilic gastroenteritis is described. This 50-year-old man presented protein-losing gastroenteropathy, iron-deficiency anemia, and marked elevation of serum IgE, in whom the lesion formed a diffuse thickening of almost the entire portion of the stomach. Microscopically, there was an intense infiltration of eosinophils throughout the whole thickness of the gastric wall, interspersed with plasma cells and lymphocytes. On the affected area, an increased number of IgE-positive plasma cells and surface IgE-positive mast cells, some of which are degranulated, were identified. These immunohistochemical findings provide a strong evidence for IgE mast cell-mediated allergy concerning this disorder.