PDGFRB and Increased total eosinophil count: For this reason, the 2008 WHO Classification of hematopietic and lymphoid tumors has introduced a separate diagnostic category for such disorders, referred to as “Myeloid and Lymphoid Neoplasms with Eosinophilia and Abnormalities of PDGFRα, PDGFRβ or FGFR1” [58].