Primary Gastric Lymphoma Following Kidney Transplantation - Closer Look at the Mucosa

An increased incidence of non-Hodgkin's lymphoma is seen in patients with immunodeficiency from any cause. The majority of these are high grade B-cell lymphoma and most are associated with the Epstein-Barr virus (EBV) In post-transplant lymphoma/lymphoproliferative disorders the tumour may regress following reduction of immunosuppression but in AIDS the lymphomas show a characteristic aggressive course and poor prognosis. Although it is now accepted that the development of gastric mucosa associated lymphoid tissue (MALT) lymphoma is preceded by H pylori infection, there is no clear evidence indicating that immunosuppression increases the incidence of H pylori infection, or that H pylori is implicated in the pathogenesis of PTLD. Because of the truly lymphomatous phenotype of EBV-negative late-developing PTLD, H pylori infection may represent a pathogenic factor especially in MALT lymphoma type. However, clinical and morphologic data suggest that at least some high-grade lymphomas of the stomach may develop from low-grade mucosa-associated lymphoid tissue (MALT) lymphomas. In MALT lymphoma, advanced tumor stages (EII), or tumors with transition to high-grade malignancy did not respond to eradication of the H pylori infection. The possibility for complete remission in high-grade lymphomas needs to be investigated in prospective studies. Therapy to eradicate H pylori should not replace conventional treatment; bacterial eradication should be considered as a component of therapy for gastric large-cell lymphoma.