Morphology and immunophenotype of neoplastic cells in cases classified as lymphocyte predominance Hodgkin disease (LPHD).

(A) In all cases neoplastic cells with folded and lobated nuclei were observed (H&E-stained). (B) In more than half of the cases, there was a varying number of neoplastic cells with features of Reed-Sternberg (RS) cells of classical HD (arrows, H&E-stained). (C) and (D) Both types of tumor cells (an RS cell is highlighted by an arrow) showed a strong expression of the CD20 antigen (immunostain with the anti-CD20 monoclonal antibody L26, APAAP method with new fuchsin as chromogen). (E) A CD79a expression was also found in the neoplastic cells in most cases, its expression intensity being lower than that of CD20 (immunostain with the anti-CD79a monoclonal antibody JCB117, APAAP method). (F) Expression of J-chain was detectable in both tumor cell types (arrows indicate RS cells) of more than 90% of the cases. Insert highlights the cytoplasmic expression with labeling of the nuclear membrane (immunostain with the anti–J-chain polyclonal antibody, APAAP method). (G) EMA expression by the neoplastic cells was found in up to 50% of the cases (immunostain with the anti-EMA monoclonal antibody E29 using a peroxidase method with diaminobenzidine for development). (H) Immunostaining for CD30 (using the monoclonal anti-CD30 antibody Ber-H2 and the APAAP method) disclosed that the neoplastic cells (highlighted by arrows) did not express this antigen. The CD30⁺ cells corresponded to small mononuclear blasts.