Composite lymphoma comprising cHL and follicular lymphoma. TCA in cHL component. (A) Low-power view of the composite histologic components (H&E, ×100). (B,C) Higher-power view depicting morphologically distinct components; ie, follicular lymphoma grade 3 and cHL, respectively (H&E, ×200). (D-J) Various markers expressed within the HRS cell component with very weak and variable CD20 (D), PAX-5 (E), and BCL-6 (F) expression (immunoperoxidase, ×200, ×400, ×400). (G) These cells are EBER negative (in situ hybridization, ×400). (H-J) TCA expression in cHL component. Among the T-cell markers, there is strong CD3 (H), CD2 (I), and CD4 (J) expression on membrane of the HRS cells (immunoperoxidase, ×400, ×400, ×400). Notably, CD4 was variable in this case with adjoining scattered CD4-negative HRS cells, lending credence to the specificity of staining.