According to the latest recommendations on the classification and management of eosinophilic disorders, three entities should be considered based on the 2022 WHO and ICC classifications of myeloid neoplasms [11,24]: MLN-TK (including PDGFRA, PDGFRB, FGFR1, JAK2, FLT3, PCM1-JAK2 fusion, ETV6-ABL1 fusion, and other defined tyrosine kinase fusions) [40,54,55,56,57,58], myeloid malignancies associated eosinophilia [40], and CEL NOS [5,6]. The gene discussed is PDGFRB; the disease is eosinophil disorder.