Extensive small intestinal T-cell lymphoma of low-grade malignancy associated with a new chromosomal translocation

Primary T-cell lymphoma of the small intestine is rare, and most cases have proved rapidly fatal.

We describe a case of lymphoma involving the small intestine uniformly and extensively in a 28-year-old man on initial examination seen with long-standing diarrhea, malabsorption, and recurrent episodes of intestinal obstruction. Clinical remission was obtained with pentostatin (2'-deoxycoformycin, supplied 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, mesenteric lymph nodes and peripheral blood cells were studied for T-cell receptor (TCR) gene rearrangement and karyotype.

Lymphoma cells were small T-lymphocytes with irregular pleomorphic nuclei, bearing the CD3, CD4 and TCR alpha-beta phenotype. Peripheral-blood cytology and bone marrow biopsy were normal. Southern blot analysis of the TCR beta-chain gene revealed the same monoclonal rearrangement in the mesenteric lymph nodes and peripheral blood lymphocytes. An as yet undescribed t(4;16)(q26;p13) translocation, involving the region where the interleukin-2 (IL-2) gene has been mapped, was present in the mesenteric lymph nodes and peripheral blood lymphocytes.

We believe this 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 chromosomal translocation.