ACUTE PROMYELOCYTIC LEUKEMIA WITH HYPOGRANULAR BONE-MARROW BLASTS IN A 16-YEAR-OLD GIRL - DIAGNOSTIC-VALUE OF DIFFERENT GENETIC METHODS

We report a 16-year-old girl who presented with anaemia, thrombocytope nia, leukocytosis and disseminated intravascular coagulation. Bone mar row analysis showed promyelocyte-like myeloblasts with rare Auer rods and very few granula. CD2 antigen was not expressed in bone marrow bla sts. Karyotype analysis revealed a complex pattern of chromosomal aber rations without the promyelocytic leukaemia (PML) specific translocati on t(15;17) (q22;q21). Southern blot analysis revealed a rearrangement of the retinoic acid receptor alpha (RAR alpha) locus. Reverse transc ribed polymerase chain reaction assay confirmed the initial diagnosis of PML by amplification of the PML-specific PML/RAR alpha fusion trans cript. Conclusion This case report confirms that a characteristic tran slocation t(15;17) is not always detectable in PML blasts by karyotype analysis despite presence of specific PML/RAR alpha-transcripts. Toge ther with careful morphological analysis of bone marrow blasts this as say apparently is the most specific and sensitive method to confirm th e diagnosis.