Testicular Lymphoma : CD20
Immunohistochemical Profile of Primary Diffuse Large B-cell Lymphoma (DLBCL) of the Testis: Analysis reveals a non-germinal center B-cell immunophenotype with a high proliferation index in 90% of cases. Like other locations, DLBCL in the testis expresses CD45 and pan B-cell markers (CD20, CD22, CD79a), and PAX-5. The image shows CD20 immunostain. Monotypic immunoglobulin (surface or cytoplasmic) is variably present. Other positive markers include CD10 (40% cases), BCL6 (60% cases), and BCL2 (50% cases). Although BCL2 protein expression is frequent, BCL2 translocation is usually absent. CD5 is present in about 10% of cases. A small percentage of cases show post-germinal center or plasma cell-associated markers such as CD38, VS38, and MUM1. Ki-67 labeling index is high (>20%). A minority of cases express CD30. Pan-T markers are negative. There is no association with Epstein-Barr Virus or Human Herpes Virus 8.