α-heavy chain disease, Mediterranean lymphoma, and immunoproliferative small intestinal disease A review of clinicopathological features, pathogenesis, and differential diagnosis

There are a number of clinical syndromes associated with chronic diarrhea, malabsorption, and lymphoplasmacytic proliferation of the small intestine. In Middle-Eastern and Mediterranean countries immunoproliferative small intestinal disease is endemic, whereas in other parts of the world (including Northwestern Europe and North America) celiac sprue, and other sprue-like syndromes refractory to dietary gluten withdrawal, predominate. All of these syndromes appear to involve chronic stimulation of intestinal mucosa-associated lymphoid tissue and are associated with a heightened risk of malignant transformation. The clinicopathological features of these diseases, and distinction of the Middle Eastern syndromes from those more common in the Western hemisphere, have been reviewed.