![Figure 1.](/tables/jh27w-g001.jpg)
Figure 1. Morphological appearance of Castleman disease diagnosed at initial lymph node sampling. Compressed and partially hyalinized germinal centre surrounded by mantle zone B-cells HE, (A). Residual GC are highlighted by CD10 immunostaining of the same region (B) and remain negative by CD20 due to involution and hialinization (C). Diffuse large B-cell lymphoma showing solid areas of large CD20+ cells (D, E). MUM1 positivity supports the activated B-cell origin of the change (F).
![Figure 2.](/tables/jh27w-g002.jpg)
Figure 2. Castleman disease showed activity in many lymphatic areas (A). During staging of DLBCL significant progression was detected in the infradiagphragmatic region with bone marrow involvement (B). After 2 cycles of R-CHOP interim PET/CT proved improvement in the supradiaphragmatic, but not in the infradiaphragmatic region. After several chemotherapeutic protocols refractory state was confirmed by PET/CT and clinical signs (D). Arrows show the involved lymph nodes, spleen, lung and bone marrow. Arrows shows tracer enhanced areas.