Image Description
Nodal Architecture in Angioimmunoblastic T-cell lymphoma (AITL) : The architectural changes in AITL have been divided into three patterns. These patterns represent different stages of disease progression. Pattern 1 (20% of cases): It is the earliest stage with preservation of nodal architecture and the presence of hyperplastic follicles. Pattern 2 (30% of cases): The nodal architecture is largely effaced except for occasional depleted follicles or "burned-out" germinal centers (shown in this image). Pattern 3 (50% of cases): The nodal architecture is completely lost with no B-cell follicles (burned-out or otherwise).
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.