EXTENSIVE SMALL-INTESTINAL T-CELL LYMPHOMA OF LOW-GRADE MALIGNANCY ASSOCIATED WITH A NEW CHROMOSOMAL TRANSLOCATION

Background. Primary T-cell lymphoma of the small intestine is rare, an d most cases have proved rapidly fatal. Methods. We describe a case of lymphoma involving the small intestine uniformly and extensively in a 28-year-old man on initial examination seen with longstanding diarrhe a, malabsorption, and recurrent episodes of intestinal obstruction. Cl inical remission was obtained with pentostatin (2'-deoxycoformycin, su pplied by Professor Catovsky, London UK) after the patient had failed to improve under conventional chemotherapy. Tumor specimens as well as mesenteric lymph node, liver, and bone marrow specimens were studied with conventional pathology and immunochemistry. Additionally, mesente ric lymph nodes and peripheral blood cells were studied for T-cell rec eptor (TCR) gene rearrangement and karyotype. Results. Lymphoma cells were small T-lymphocytes with irregular pleomorphic nuclei, bearing th e CD3, CD4 and TCR alpha-beta phenotype. Peripheral-blood cytology and bone marrow biopsy were normal. Southern blot analysis of the TCR bet a-chain gene revealed the same monoclonal rearrangement in the mesente ric lymph nodes and peripheral blood lymphocytes. An as yet undescribe d t(4;16)(q26;p13) translocation, involving the region where the inter leukin-2 (IL-2) gene has been mapped, was present in the mesenteric ly mph nodes and peripheral blood lymphocytes. Conclusion. We believe thi s is the first description of an extensive, small intestinal lymphoma of low-grade malignancy made up of monoclonal T-cells with a TCR alpha -beta and helper/inducer phenotype, associated with a novel chromosoma l translocation.