Chronic myeloid leukaemia occurring in a patient with hairy cell leukaemia.

Occurrences of second malignancies in hairy cell leukaemia are well recognised. Most of these malignancies are either solid tumours or lymphoproliferative disorders. The association of myeloproliferative disorders with hairy cell leukaemia (HCL) is very rare. This report describes a case of a patient with HCL who after remaining in remission developed Philadelphia chromosome positive chronic myeloid leukaemia (CML), which rapidly transformed to acute lymphoblastic leukaemia with further cytogenetic abnormalities.