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 ?
TeamHaem 