Simultaneous appearance of trisomy 8 and trisomy 12 in different cell populations in a patient with untreated B-cell chronic lymphocytic leukemia and myelodysplasia.

The co-existence of spontaneously arising myeloid and lymphoid malignancies in the same patient is rare, and is thought to be mainly due to chance. We describe a patient presenting simultaneously with chronic lymphocytic leukemia (CLL) and myelodysplasia (MDS). Histological, flow cytometric, chromosomal and fluorescent in situ hybridization (FISH) studies show that both cell populations possess different sets of markers consistent with the myeloid and lymphoid differentiation pathways. The question of whether these arose from a single or two separate progenitor cells is explored.