title: PDGFRalpha/FIP1L1-positive chronic eosinophilic leukemia presenting with retro-orbital localization: efficacy of imatinib treatment.
abstract: BACKGROUND
  The fusion protein between the platelet-derived growth factor receptor alpha (PDGFRalpha, P) gene and the Fip1-like1 (FIP1L1, F) may be identified in 14 to 60% of HES and it indicates a clonal hypereosinophilic syndrome called F/P-positive CEL. We herein report a case of F/P-positive CEL with retro-orbital localization, who was successfully treated with imatinib.
  
  
  METHODS
  A 53-year-old male presented an absolute eosinophil count of 25,000/mm(3), anemia (Hb 10.2 g/dl) and a moderate increase in the platelet count (571,000/mm(3)). A clinical examination revealed left exophthalm, associated with diffuse hypoesthesia and diplopia. A CT scan of orbits showed a lesion located in the lachrymal fossa of the left orbit with intra- and extra-conical extension. Molecular analysis excluded the presence of bcr/abl transcript while a F/P fusion tyrosine kinase signal was documented. Imatinib mesylate (IM) was started and, after 7 days of treatment eosinophil count significantly declined along with a dramatic reduction of the left exophthalm. IM dosage was increased up to 300 mg/day. The drug was well tolerated with an initial modest haematological toxicity. The left exophthalm, as well as hypoesthesia and diplopia, disappeared after IM therapy. MRI showed a clear reduction of the intra- and extra-conical growth process. BM molecular signal of the F/P fusion gene resulted undetectable after 4 weeks of treatment.
  
  
  CONCLUSIONS
  In our case, the diagnosis of FIPIL1-PDGFRA-positive CEL and IM therapy has allowed the patient to experience an excellent clinical therapeutic result, avoiding surgical treatment of the retro-orbital mass.
authors.affiliation: Unità Operativa di Ematologia Medicine, Cosenza, Italy.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Vigna
authors.forename: Eugenio
authors.initials: E
authors.lastname: Lucia
authors.forename: Massimo
authors.initials: M
authors.lastname: Gentile
authors.forename: Carla
authors.initials: C
authors.lastname: Mazzone
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Bisconte
authors.forename: Carlo
authors.initials: C
authors.lastname: Gentile
authors.forename: Antonio
authors.initials: A
authors.lastname: Armentano
authors.forename: Emanuela
authors.initials: E
authors.lastname: Ottaviani
authors.forename: Michela
authors.initials: M
authors.lastname: Rondoni
authors.forename: Giovanni
authors.initials: G
authors.lastname: Martinelli
authors.forename: Fortunato
authors.initials: F
authors.lastname: Morabito
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D006801:Humans; D017681:Hypereosinophilic Syndrome / Q000188:drug therapy* / Q000235:genetics*; D000068877:Imatinib Mesylate; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015514:Oncogene Proteins, Fusion / Q000378:metabolism*; D009918:Orbital Neoplasms / Q000188:drug therapy* / Q000235:genetics*; D010879:Piperazines / Q000627:therapeutic use*; D011743:Pyrimidines / Q000627:therapeutic use*; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014057:Tomography, X-Ray Computed; D039221:mRNA Cleavage and Polyadenylation Factors / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D015514:Oncogene Proteins, Fusion; D010879:Piperazines; D011743:Pyrimidines; D039221:mRNA Cleavage and Polyadenylation Factors; D000068877:Imatinib Mesylate; C479819:FIP1L1-PDGFRA fusion protein, human; D020796:Receptor, Platelet-Derived Growth Factor alpha