Image Description
Proliferation of B-cell blasts is a common finding in angioimmunoblastic T-cell lymphomas. They resemble centroblasts, immunoblasts, or Hodgkin cells. They may be present as single scattered cells, small clusters, or large sheets (which may be indistinguishable from diffuse large B-cell lymphoma). Immunophenotypically, they are positive for EBV-encoded small RNA, CD20, and CD30 (shown here) and negative for CD15.
About the Disease
Angioimmunoblastic T-cell lymphoma (AITL) is a type of peripheral T-cell lymphoma arising from follicular helper T cells of the germinal center. It is a systemic disease that presents with generalized lymphadenopathy, hepatosplenomegaly, constitutional symptoms, skin rash, anemia, and polyclonal hypergammaglobulinemia. There is effacement of the normal nodal architecture with disappearance of follicles and germinal centers, a polymorphic cellular infiltrate that extends into perinodal tissues, and proliferation of high endothelial venules and follicular dendritic cells. The atypical T-cells have irregular nuclei and clear cytoplasm. Epstein-Barr virus (EBV) can be detected by in-situ hybridization in 80% to 90% of lymph nodes affected by AITL. The virus is present in transformed B-cells and is not considered to play a role in the pathogenesis. The T-cell receptor genes are clonally rearranged. AITL is a rapidly progressive disease with a median survival of under 3 years. Given the abnormal T-cell function and the immunodeficient state, the cause of death in most cases is complications from infectious diseases. Many patients with AITL also develop EBV+ diffuse large B-cell lymphoma. References:Jaffe, E. S. et al (2017). Hematopathology - Second Edition. Philadelphia, PA. Elsevier. Swerdlow S. H. et al (2017). WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues. Revised 4th Edition. Lyon, France.