ACase Of Asymptomatic Pediatric Chronic MyelogenousLeukemia With Hyperleukocytosis

Chronic Myeloid Leukemia (CML) represents 3% of pediatric leukemias. The natural history and molecular biology of pediatric CML is the same as those of older patients with CML. 95% of pediatric CML presents in asymptomatic chronic phase and the rest diagnosed in accelerated or in blast crisis stage. It is reported that patients with pediatric CML have higher white blood cell (WBC) counts and thereby have higher incidence of symptomatic leukostasis compared to adults. Sparse literature exists on particular triggers for treatment with leukapheresis (LA). We present a case of asymptomatic hyperleukocytosis (HL) secondary to pediatric CML and a brief discussion of treatment in this emergency.

To report a rare case of asymptomatic pediatric CML with HL.

A 9-year-old Caucasian male presented to his pediatrician on the outpatient basis for well child care and was found to have a WBC of > 200,000 and then was admitted to the Pediatric Intensive Care Unit for further management. Upon arrival in the PICU, pt was found to have splenomegaly (down 4-5 cm from the costal margin) and hepatomegaly (2 cm down from costal margin). CBC revealed hemoglobin of 7.4 g/dL, platelet of 883 bil/L and a total white blood cell count (WBC) of 302.7 bil/L. A differential on the WBC revealed 43.9 basophils, 24.2 blasts, and 6.1 promyelocytes. Flow cytometry showed prominent myeloid population with 5% CD34 positive myeloblasts and a prominent basophil population, consistent with morphological expression of CML. The cytogenetic analysis revealed a t(9,22)(q34;q11) translocation consistent with a Philadelphia chromosome. Pediatric Leukaphresis (LA) for cytoreduction was not available at our facility, thus he was transferred.

The HL in this patient is a direct result of his pediatric CML. The decision regarding need for cytoreduction with LA has been described in the literature for symptomatic children, but no case has been reported of when to perform LA when no symptoms of leukostasis are present.

In this case, it was discovered that the trigger(s) to perform LA is vague in the literature, as well as controversial in practice especially with well appearing children with the potential for a swift precarious demise. Further studies and meta-analyses to uncover the proper triggers for LA are warranted.

No relevant conflicts of interest to declare.