Case 151 – Update 3

So , the diagnosis is JMML – Juvenile myelomonocytic leukemia.

We will have a summary later but just a few brief points to note :

  • JMML is unique aggressive myeloproliferative/myelodysplastic disorder of infancy and early childhood caused by proliferation of cells of monocytic and granulocytic lineage.
  • Median age of onset is 2 years of age. Children typically present with fever , splenomegaly thrombocytopenia , high WBC count and monocytosis.
  • Blood film often shows leuco-erythroblastic picture and elevated Hb F for age is found is around 50% of the patients. Monocytosis is quite characteristic.
  • Bone marrow is important to rule out AML and must have fewer than 20% blasts. Bone marrow are not solely diagnostic but findings are consistent with the diagnosis.
  • Flow cytometry is often helpful to rule out other leukemias but is not diagnostic unless we are worried about progression to AML.
  • We need to rule out BCR /ABL fusion gene at presentation
  • 90% of the patients carry either somatic or germline mutations of K-RAS , N-RAS , PTPN-11 , CBL or NF1 in their leukemic cells and this has treatment implications.
  • Mutations in the genes involved in the RAS signalling pathway play a crucial role in disease pathophysiology.
  • Diagnostic criteria is as per 2016 WHO classification.

Now that we know it is JMML , what are the treatment options for this child ? Does every child need allogenic HSCT?

Can JMML’s spontaneously regress ? What are the determining factors in each scenario ?

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