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Gastrointestinal tract is the most common
site of primary extranodal lymphoma . Lymphoma accounts for 30% of small
bowel malignancies.
Primary gastrointestinal lymphoma exhibits no
evidence of liver, spleen or bone marrow involvement at the time of
diagnosis. Regional lymphnode involvement may be present.
Criteria used to classify malignant lymphoma of small bowel include:
i) Cell lineage: B or T cell lymphoma
ii) Primary or systemic nature of tumour
iii)Associated backround chronic illnesses.
Primary gastrointestinal lymphoma usually arise as a sporadic tumour.
Sporadic lymphomas, also termed the 'Westerm type' are B- cell
lymphomas which appear to arise from the B- cells of the mucosa
associated lymphoid tissue.
Some lymphomas develop in the backround of chronic diseases . Eg.
Sprue -like malabsorption syndromes, congenital immunodeficiency states,
infection with HIV following organ transplantation with immunosuppresion
(heart transplant recipients), those complicating Crohn's disease ,
hypogammaglobulinaemia with lymphoid hyperplasia, in patients with alpha
chain disease.
Ileum is commonly affected followed by jejunum and duodenum. |