Transient leukaemia: leukaemia or leukaemoid? A diagnostic dilemma.

We report a case of a newborn male who had mongoloid slant and was hypotonic at birth. Routine investigations revealed leucocytosis (WBC > 70,000/cmm) with 50% blasts in peripheral blood film. Marrow examination confirmed the excess of blasts. Karyotyping revealed 47, XY + 21 chromosomes. Due to absence of clinical symptoms, the baby was kept on follow-up without treatment. Within 7 weeks, PBF and bone marrow findings returned to normal, and the child was diagnosed as having Transient leukaemia with Down syndrome.