Aplastic anaemia associated with a Philadelphia chromosome and monosomy 7 during immunosuppressive therapy.

We describe a patient who presented with aplastic anaemia associated with the Philadelphia (Ph1) chromosome during immunosuppressive therapy and who subsequently developed myelodysplastic syndrome (MDS) with monosomy 7. Initially the patient had hypocellular fatty marrow without leukaemic blasts or dysplastic features. Chromosome analysis showed 46, XY, t(9;22)(q34;q11) during immunosuppressive therapy, but no leukaemic transformation was detected. The patient showed gradual haematologic improvement and became transfusion independent. Thereafter, bone marrow dysplasia with monosomy 7 progressed following transfusion independence. These findings indicate that multiple cytogenetic evolutions occur in aplastic anaemia during immunosuppressive therapy, and that Ph1 chromosome may play a role in bone marrow suppression rather than development of leukaemia.