[Primary lymphoma of the stomach]

Primary lymphoma of the stomach (PLS) is an uncommon neoplasm, accounting for up to 8 per cent of all malignant neoformations with this particular localization. Its development is linked to the so-called mucosa associated lymphoid tissue (MALT), wherefrom its denomination--MALT lymphoma--is derived. In the stomach, under ordinary conditions, it is nonexistent, and in most of the cases it is acquired through infection with H. pylori. In a prevailing percentage of PLS it is a matter of B-cell lymphoma with low-degree malignancy. T-cell lymphomas occur sporadically, as well as primary Hodgkin's lymphoma which is exceptionally rare. Histologically the B-cell lymphoma reiterates the structural pattern of Peyer's plaque prototype, involving also a number of non-neoplastic components. The most distinguishing cells are reminiscent of centrocytes (centrocyte-like cells--CCL)--a term adopted for all MALT-lymphoma cases. They vary considerably in terms of cytological appearance, and may even bear resemblance to Hodgkin's and Sternberg's cells. Signet-ring lymphomas, known in several variants, are also by no means ruled out. Immunohistochemical typing presupposes a definitive diagnosis being made. In case of immunosuppression (transplantation, HIV-infection) the risk of B-cell lymphomas development augment, and what is more, most of them associated with Epstein-Barr viruses characterized by a substantially more aggressive course and poor prognosis.