Figure 1

CLL/SLL and synchronous interdigitating dendritic cell sarcoma, case 3. (a) Cervical lymph node showed islands and cords of the dendritic cell neoplasm sharply segregated from areas of CLL/SLL. Magnification × 200. (b) The dendritic cells had abundant eosinophilic cytoplasm, lobulated and indented nuclei, vesicular chromatin and variably prominent nucleoli. Some cells showed highly polylobated nuclei. The CLL/SLL cells were small with round nuclei, coarse chromatin and scant cytoplasm. Magnification × 400. (c) The dendritic cells were strongly positive for S100, and partially positive for CD68. (d) They showed strong staining for PU.1 and weak and partial staining for CEBPβ, but were negative for PAX5. The CLL/SLL cells were strongly positive for PAX5 and negative for PU.1 and CEBPβ. (e) The CLL/SLL and dendritic cells showed identical clonal peaks by PCR of the IGK@ gene (IGK tube A PCR reaction). (f) Both the CLL/SLL and dendritic cell tumor showed deletion of chromosome 17p by using the FISH probe for p53 (17p13). A control probe for chromosome 17 centromere (D17Z1) showed no loss of chromosome 17.