title: Sudden extramedullary blast crisis of chronic myeloid leukemia manifesting as T-cell lymphoblastic lymphoma.
abstract: BACKGROUND
  Chronic myeloid leukemia (CML) is usually diagnosed in the chronic phase. An extramedullary blast crisis mimicking a T-cell lymphoma is a rare finding.
  
  
  METHODS
  A 35-year-old man presented with multiple lymphadenopathy 2 months after diagnosis of Philadelphia chromosome (Ph)-positive CML in the chronic phase. Cervical lymph node biopsy later indicated an extramedullary blast crisis resembling T-cell lymphoblastic lymphoma (TLBL). The tumor mass was composed of primitive lymphoid cells expressing terminal deoxynucleotidyl transferase (TdT), CD3, CD43, CD5, CD99, and Bcl-2. Although the pathological diagnosis, confirmed by 2 independent pathological centers, was more typical of TLBL, fluorescence in situ hybridization (FISH) analysis showed the bcr-abl fusion gene within the blastic tumor cells. The FISH finding confirmed that the mass represented an extramedullary, immature blastic transformation of CML rather than a de novo T-cell lymphoma.
  
  
  CONCLUSIONS
  The diagnosis of de novo TLBL should be suspected before excluding the extramedullary blast phase of CML.
authors.affiliation: Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Wei
authors.forename: Mei
authors.initials: M
authors.lastname: Huang
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Zhou
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000235:genetics*; D001752:Blast Crisis / Q000175:diagnosis* / Q000235:genetics*; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D016399:Lymphoma, T-Cell / Q000175:diagnosis* / Q000235:genetics*; D008297:Male
chemical_list: D014408:Biomarkers, Tumor; D016044:Fusion Proteins, bcr-abl