6th ESACP Congress, Heidelberg, April 7-11, 1999

A043
BILATERAL OR MIRROR IMAGE SYMMETRY OF CHROMOSOME DISTRIBUTION IN BINUCLEATE REED-STERNBERG (RS)-LIKE CELLS BY FISH SIGNALS
Chauduri JP, Führer M, Reith A, Walther JU

Kinderpoliklinik, LMU-München, Germany, The Norwegian Radiumhospital and Cancer Institute, Oslo, Norway

RS cells observed in Hodgkines disease are large, tetra- or polyploid cells with bi- or multilobed nuclei and cell surface antigens claimed to be positive for CD 15, 30 and 70. They are considered to be of disputed lineage and ambivalent clonality. RS-like cells have also been reported in solid tumours. We shall report here on features of RS-like cells in mitotic and interphase stages observed in the bone marrow of myelodysplastic syndromes (MDS) and severe aplastic anaemia (SAA). Higher magnifications (63x or 100x oil immersion) revealed binucleate cells with generally tetraploid nuclei with bi- or multilobed morphology, demonstrating prominent bilateral or mirror image symmetry as shown by the distribution of chromosome specific FISH signals. In one patient with a high frequency of RS-like cells a metaphase showed a mirror image symmetry punctuated by the sex chromosome FISH signals. Similar symmetric chromosome distribution have been observed in diploid bilobed nuclei of granulocytes (Chaudhuri, Reith. Analytical and Quantitative Cytology and Histology, 1997, 19: 30-36). The reported features of these RS-like cells in mitotic and interphase stages may have implications on a better understanding of their cytopathology, cytogenetics and clonality.