Hypereosinophilic syndrome (HES) is a rare clinical entity defined by a persistent absolute eosinophil count (AEC) of 15 000/μL for longer than 6 months, organ damage, and exclusion of reactive eosinophilia or other hematologic cancers described by the World Health Organization.1,2 (To convert eosinophils to ×109/L, multiply by 0.001.) Skin manifestations are common, affecting up to 50% of patients with HES. Skin findings include vesicles, petechiae, angioedema, livedo reticularis, necrosis, gangrene, Raynaud phenomenon, eosinophilic cellulitis and vasculitis, urticaria, symmetrical hyperkeratosis, mucosal ulcerations, and pruritus.3 We now know that hypereosinophilia is often associated with predictable genetic alterations and rearrangements, understanding of which is crucial to guiding therapy. We describe a patient with a novel inversion of chromosome 5 (inv(5)) involving PDGFRB gene rearrangement and hypereosinophilic syndrome successfully treated with imatinib.
Saultz JN, Kaffenberger BH, Taylor M, Heerema NA, Klisovic R. Novel Chromosome 5 Inversion Associated With PDGFRB Rearrangement in Hypereosinophilic Syndrome. JAMA Dermatol. 2016;152(12):1391-1393. doi:10.1001/jamadermatol.2016.3175