Natural killer-like T-cell lymphoma of the small intestine with a distinct immunophenotype and lack of association with gluten-sensitive enteropathy.

We report the case of a large natural killer (NK)-like T-cell lymphoma that involved the ileum and displayed a distinct immunophenotype and complex karyotype. The patient exhibited no evidence of gluten-sensitive enteropathy (celiac disease) or any other type of enteropathy as determined by clinical history, endoscopy, and serology for immunoglobulin A (IgA) antiendomysial and IgG antigliadin antibodies. Molecular studies demonstrated a clonal T-cell receptor gamma chain gene rearrangement. Immunophenotype analysis showed expression of intestinal epithelium-homing receptor CD103, CD7, cytoplasmic CD3 epsilon, CD56, and CD16 but no other T- or NK-cell markers. Cytogenetic analysis of the malignant cells revealed multiple chromosomal abnormalities indicative of a biologically advanced, high-grade lymphoma. A novel subset of normal intestinal intraepithelial lymphocytes, bearing a similar phenotype, has been described; moreover, this subset diminishes, rather than expands, in gluten-sensitive enteropathy. This case supports the notion that lymphomas involving the small intestine represent a heterogeneous group of lymphomas with diverse pathogenetic mechanisms.