Figure 1.

CD30 expression (A) representing Hodgkin–Sternberg–Reed (HRS) cells and partially carbonic anhydrase IX (CAIX) positivity (B) demonstrating hypoxia-related adaptation in a subset of the neoplastic compartment surrounded by reactive cell masses characteristic for classical Hodgkin’s lymphoma (cHL). Variable levels of membrane/cytoplasmic CAIX expression could be observed in the neoplastic HRS cells while the non-neoplastic background remained virtually negative. Samples with necrosis showed intense CAIX expression in the perinecrotic area (arrows). Asterix indicates the center of the necrotic area. Scale bar = 100 μm.