Figure 3

CLL/SLL and synchronous histiocytic sarcoma, case 7. (a) An axillary lymph node was mostly effaced by sheets of CLL/SLL cells with a focal nodule composed of atypical histiocytic cells. Magnification × 40. (b) The histiocytic sarcoma cells were very large with round nuclei, vesicular chromatin, prominent central nucleoli and voluminous pink cytoplasm. Some cells showed emperipolesis. Magnification × 100. (c) The CLL/SLL cells were positive for CD79a, CD5 and CD23. The histiocytic sarcoma cells were strongly positive for CD163. (d) They were partially positive for S100 and showed strong staining for PU.1 and CEBPβ. They were negative for PAX5. (e) The CLL/SLL and histiocytic sarcoma cells showed identical clonal peaks following IGH@ FRIII PCR (upper panel). Sequencing of the IGH@ gene rearrangements (lower panel) showed complete sequence identity between that of CLL/SLL and the histiocytic sarcoma cells. The asterisks indicate identical DNA sequence. The solid lines indicate corresponding V, D and J genes. The DNA sequences between the solid lines are V–D and D–J junctional sequences. (f) Both the CLL/SLL and IDCS 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. In addition, the histiocytic sarcoma showed deletion of chromosome 13q by using the FISH probe D13S319 (13q14.3). The CLL/SLL cells showed no abnormality in chromosome 13.