M3-variant of acute promyelocytic leukaemia. A case report in a Malay boy.

The variant form of acute promyelocytic leukaemia (AML-M3) possesses its own characteristic morphology, although usually a few of the cells may have cytoplasmic features of typical AML-M3. In contrast to typical AML-M3, this M3-variant form commonly presents with hyperleucocytosis. As in typical AML-M3, disseminated intravascular coagulopathy (DIVC) occurs in the M3-variant. A boy with this morphological variant of AML-M3 is described. Uncharacteristically, his presenting white blood count was low, and DIVC was present before treatment was started. Six days into intensive chemotherapy his coagulopathy worsened and he subsequently died of intracranial haemorrhage. An alternative approach to the treatment of AML-M3, with the use of retinoids, is discussed.