摘要：

The majority of extranodal non-Hodgkin's lymphomas occur in the gastrointestinal tract and other mucosal organs where the tumours arise from mucosa associated lymphoid tissue (MALT). This lymphoid tissue may be a normal tissue component as in the mucosa of the intestine and bronchi, or acquired, usually as the result of an 'autoimmune' disorder as in the stomach, salivary glands and thyroid. In either case, the organization and histological features of the lymphoid tissue are distinctive and differ from that of peripheral lymph nodes. As a consequence, the clinicopathological features of the lymphomas derived from MALT are equally distinctive, differing from the much more common nodal lymphomas 1 . At present, studies of MALT derived lymphomas have principally been confined to those of B-cell origin. These appear to account for the great majority of this group of lymphomas. It is conceivable that an equally distinctive group of T-cell lymphomas arises from MALT, and the recent characterization of coeliac associated lymphoma as a T-cell neoplasm 2 suggests that this is indeed the case. The clinicopathological features of MALT derived lymphomas can only be fully comprehended in relation to the histology and physiologic behaviour of MALT. Thus the cells of these lymphomas share the homing patterns of MALT lymphocytes and this may account for the slow evolution of the lymphomas and their tendency to remain localized. Certain specific and diagnostically useful histological features common to these lymphomas can also be explained in relation to their origin from MALT.

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