FIP1L1-PDGFRA is a relatively infrequent but treatment-relevant mutation in primary eosinophilia that is indicative of an underlying systemic mastocytosis.
Patients with FIP1L1-PDGFRA fusion presented with more bone marrow eosinophils and peripheral blood eosinophilia as well as anemia, leukocytosis and thrombocytopenia.
We report a 29-year-old man with double hip pain and lower limb weakness for 6 months with myeloid neoplasm with FIP1L1-PDGFRA rearrangement without marked peripheral blood eosinophilia.