Myeloid neoplasm with PDGFRA rearrangement presenting in blast-phase with basophilia.
Anne-Cecilia van Marle, Evan Bowen
✦ AI-curated · Sources linked
Case in brief
An adult man from Southern Africa presented with progressive fatigue. Blood morphology showed marked basophilia and 21% myeloblasts, with flow cytometry supporting a provisional diagnosis of acute myeloid leukaemia with basophilia. Bone marrow biopsy showed increased mast cells, raising systemic mastocytosis as another possibility. Next-generation sequencing detected a PDGFRA fusion, establishing blast phase of a myeloid/lymphoid neoplasm with PDGFRA rearrangement. Abnormal basophilic granulation, absent peripheral blood eosinophilia and delays in specialised testing contributed to diagnostic difficulty.
What made this case unusual
The blast-phase neoplasm presented with marked basophilia but no peripheral blood eosinophilia, while marrow mast-cell increase suggested a competing diagnosis of systemic mastocytosis.
Diagnostic / clinical pearl
When basophilia, blasts and increased marrow mast cells create overlapping morphologic diagnoses, molecular testing can identify a PDGFRA fusion and clarify the underlying neoplasm.
Why it matters
The report notes that these tyrosine kinase fusion-driven malignancies are highly responsive to targeted therapy, making timely molecular diagnosis clinically important.