The RS cells/variants were positive for CD30 and CD15, and showed down-regulation of B-cell program and CD45, an immunophenotypic profile consistent with cHL.
Although CD20 was negative and PAX5 and CD45 were down-regulated, the pleomorphic large cells expressed multiple other B-cell antigens which are characteristically absent in cHL.
Immunohistochemical studies revealed that the large atypical cells were CD30 (+), CD15 (weakly +), CD20 (-), CD45 (-), Pax5 (weakly +), BOB.1 (-), and Oct2 (-), indicating the coexistence of SMZL with cHL.