Image Description
CD15: CD15 is a carbohydrate antigen recognized with LeuM1 and other antibodies. It is a myeloid/monocyte marker that plays a role in phagocytosis and chemotaxis. It is positive in Reed-Sternberg (RS) cells and variants in about 80% of classic Hodgkin lymphoma (cHL) cases. The pattern of staining is typically membranous, with paranuclear, dot-like Golgi accentuation. Strong expression in eosinophils and neutrophils may obscure the staining of RS cells.
CD15 is quite useful in differentiating RS cells from RS-like cells or CD30 positive reactive blasts seen in other conditions. Co-expression of CD15 and CD30 is infrequently seen outside of the setting of cHL.
About the Disease
Classic Hodgkin lymphoma (cHL) is an uncommon malignant neoplasm of germinal-center B-cell origin that is primarily seen in young adults and, less commonly, in elderly patients. It usually arises in a single node or group of nodes and shows orderly spread to contiguous lymphoid tissues. The neoplastic cells - known as Hodgkin and Reed-Sternberg cells - make up only about 1% of all the cells in the involved lymph node or tissue. They express cell surface CD30 antigen and are present in a microenvironment rich in immune effectors cells. Four histologic subtypes are recognized in the current classification - nodular sclerosis, mixed cellularity, lymphocyte-rich, and lymphocyte-depleted. In about 5% of cases, a subtype cannot be specified due to insufficient material for a complete analysis. The prevalence of Epstein-Barr virus and its role in the pathogenesis depends upon the subtype. cHL is highly sensitive to radiation and chemotherapy and is characterized by a high cure rate, even in advanced stages. Several novel therapies targeting specific molecular pathways have been developed to treat refractory cases. The comments accompanying the images have been derived from the following sources: References:Jaffe, E. S. et al (2017). Hematopathology - Second Edition. Philadelphia, PA. Elsevier. Goldblum, J. R. et al (2018). Rosai and Ackerman's Surgical Pathology - 11th Edition. Philadelphia, PA. Elsevier. Kumar, V., Abbas, A. K., & Aster, J. C. (2021). Robbins and Cotran Pathologic Basis of Disease - Tenth Edition. Philadelphia, PA. Elsevier. Connors, J. M. et al. Hodgkin Lymphoma. Nature Reviews. Disease Primers (2020) 6:61. Kuppers R, Engert A, & Hansmann M. Hodgkin Lymphoma. J Clin Invest. 2012; 122(10):3439-3447.