An unusual case of peripheral T-cell lymphoma with CD56 positivity and angiocentric, angiodestructive morphology arising in the ileum

Primary intestinal intraepithelial natural killer-like T-cell lymphoma: case report of a distinct clinicopathologic entity

Intestinal T-cell lymphoma is a heterogenous group. These tumors differ in their association with enteropathy, intraepithelial or nonintraepithelial origin, primary or secondary involvement, and T-cell or natural killer-like T-cell immunophenotype. There are also nonneoplastic conditions, such as celiac disease, refractory sprue, and reactive T-cell infiltration that mimic intestinal T-cell lymphoma. Therefore, the differential diagnosis requires extensive morphologic, immunophenotypic, and molecular genetic studies. A subset of primary intestinal intraepithelial T-cell lymphoma has emerged in recent years that is distinguished from enteropathy-type T-cell lymphoma in terms of clinical presentation (nonenteropathic), morphology (monomorphic small to medium-sized cells), immunophenotype (CD3(-)CD8(+)CD56(+)), and cytogenetics. We report such a case with a unique immunophenotype (CD3(-), cytoplasmic CD3(+), CD4(-), CD8(+), CD5(-), CD7(+), CD16(-), CD56(+), CD57(-), CD103(+), T-cell intracellular antigen 1(+), and betaF1(+)) that is comparable to that of a newly identified subset of intraepithelial T cells. The tumor progressed rapidly and the patient died within 6 months after the onset of the disease. We recommend a large monoclonal antibody panel for the differential diagnosis of this heterogeneous group of T-cell lymphoma.

CD8+, CD56+ (natural killer-like) T-cell lymphoma involving the small intestine with no evidence of enteropathy: clinicopathology and molecular study of five Japanese patients

The present study reports five CD8+, CD56+ (natural killer (NK)-like) T-cell lymphomas involving the small intestine without evidence of enteropathy, from Japan. Three were intestinal T-cell lymphoma. The site of origin of the other two was not definitive. Four of five patients underwent emergency operation because of intestinal perforation. The small intestines of these patients had multiple ulcerative lesions with or without demarcated tumors. Histologically, the lymphoma cells were monomorphic or slightly pleomorphic and displayed epitheliotropism of varying degrees. Lymphoma cells of all patients shared the common phenotype: CD3+, CD4-, CD5-, CD8+, CD56+, CD57-, T-cell intracellular antigen-1+, granzyme B+. In contrast to nasal/nasal type NK-cell lymphomas, they had clonal rearrangement of T-cell receptor(TCR) genes and were negative for EBV-encoded RNA. Immunohistochemistry and genetics suggested that three cases were of alpha beta T-cell origin and two cases were of gamma delta T-cell origin. There was no evidence of enteropathy in any patient. The cases followed a clinically aggressive course with a frequent involvement of lung. According to the classification based on the recent genetic studies of European enteropathy-type intestinal T-cell lymphoma (ETL), the present cases could be classified as type 2 ETL.