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[ALK positive large B-cell lymphoma: a case report].

Objective To study clinicopathologic features of ALK-positive large B-cell lymphoma.Methods The clinical data,histopathological characteristics,immunophenotype and fluorescence in situ hybridization (FISH) result of a patient with ALK-positive large B-cell lymphoma were analyzed and discussed combined with related literatures.Results A 30-years-old male patients with the left neck lymphadenectasis was studied.Histological evaluation revealed the tumor grew in sheets in the nodal,with round nuclei,dispersed chromatin,a single prominent central nucleolus and moderate amounts of eosinophilic to amphophilic cytoplasm.The neoplastic cells exhibited immunoblastic/plasmablastic morphology.Immunohistochemistry measurement showed that the tumor cells were marked positively by CD138,ALK-1,CD45RO,CD4,Perforin,CD117 and Kappa proteins,while negatively by CD3,CD8,CD20,CD30,CD38,CD57,CD79a,Pax-5,EMA and AE1/AE3 proteins.FISH test demonstrated the presence of ALK gene translocation.The patient was given 4 cycles of CHOP chemotherapy after surgery.However,the conditions deteriorated after 4 months.Now the patient continued to receive treatment.Conclusion ALK-positive large B-cell lymphoma represents a distinct variant of diffuse large B-cell lymphoma,and the tumor has special histological features along with a distinct immunophenotype and ALK gene rearrangement. 
 
Key words: 
ALK-positiv large B-cell lymphoma;  Immunophenotype;  In situ hybridization, fluorescence;  Differential diagnosis