GI-lymphomas in immunosuppressed patients (organ transplantation; HIV).

Gastrointestinal lymphoma plays a major role complicating different diseases presenting with immunosuppression, both primary and acquired immunodeficiency (incl. HIV, transplantation, immunosuppression following chemotherapy, or inflammatory bowel disease). Lymphoma in diseases with immunosuppression are clinically and pathologically heterogeneous, but share some features such as frequent involvement of extranodal sites, diffuse aggressive histology, B-cell lineage derivation, viral association with EBV and clinically aggressive courses. While gastrointestinal lymphoma in congenital immunodeficiency disorders seems to be a rare event inspite of higher prevalences, in post-transplant lymphoproliferative disorders (PTLD) the gastrointestinal tract is one of the most important organs of lymphoma. In HIV-associated non-Hodgkin's lymphoma, gastrointestinal lesions as the most frequent extranodal localisation occur in 30-50% of lymphoma patients, are late events of HIV infection with severe immunosuppression and are mainly diagnosed with advanced disease stages Ann Arbour III or IV. They are characterised by unusual, often multifocal localisation in the gastrontestinal tract, high rates of life-threatening complications (bleeding, perforation or obstruction) and high-grade B-cell histology. With the introduction of highly active antiretroviral therapy (HAART) in the therapeutic concept in AIDS, a decrease of AIDS-related GI lymphoma was noted with improved survival rates and prognosis of lymphoma. Therapy strategies including chemotherapy, immunotherapy and HAART will show promising results in response and survival rates. 2010 Elsevier Ltd. All rights reserved.