Primary gastrointestinal lymphoma

Summary

Despite the fact that the gastrointestinal tract is the commonest site of extranodal malignant lymphoma, gastrointestinal lymphomas remain poorly characterised. Attempts to fit gastrointestinal lymphoma into the newer classifications have been hampered by its relative rarity (at least in “Western” countries) and the poor fixation of specimens which so often bedevils gastrointestinal pathology as a whole. Apart from the overall classification there are two other aspects of gastrointestinal lymphoma that are of particular interest. These are the nature of the intestinal lymphoma that occurs as a complication of coeliac disease and the gastrointestinal lymphomas that occur so commonly in the Middle East. As newer techniques have begun to be applied to gastrointestinal lymphomas a measure of agreement over their classification is emerging. Controversy continues, however, over coeliac disease associated lymphoma particularly with regard to the recently described entity of malignant histiocytosis of the intestine. Interest in gastrointestinal lymphoma, which occurs with such high frequency in the Middle East, is directed principally at the entity called Mediterranean lymphoma which is characterised by malabsorption and plasma cell infiltration of the intestinal lamina propria. In some of these cases α-heavy chain paraprotein is present in the serum or duodenal juice. There is considerable debate as to whether the plasma cell infiltrate is itself neoplastic and also as to the nature of the lymphoma that evolves in this setting. A great deal of work remains to be done in the field of gastrointestinal lymphoma with particular reference to coeliac disease and α-chain disease. Morphological studies alone are insufficient and the application of newer techniques is essential if we are to increase our understanding of this important group of diseases.