title: A case of natural killer cell leukemia misdiagnosed as tuberculous lymphadenopathy.
abstract: Natural killer (NK) cell neoplasms are a group of rare but highly malignant tumors. We report here one case of NK cell leukemia. A 54-yr-old woman presented with a 2-month history of progressive left neck mass. Based on the positive result of tissue PCR for Mycobacterium tuberculosis, she was at first diagnosed with tuberculous lymphadenopathy. After two weeks, she developed generalized lymphadenopathy, hepatosplenomegaly, fever and anemia. Subsequent evaluation was performed including bone marrow aspiration and biopsy. Peripheral blood smear showed leukoerythroblastic features with 31% blasts. Bone marrow was packed with agranular blastoid cells, which were periodic acid-Schiff (PAS) positive and myeloperoxidase (MPO) negative. Immunophenotyping showed that these cells were positive for CD45 and HLA-DR, whereas negative for CD3, CD5, CD7, CD10, CD13, CD14, CD19, CD20, CD22, CD33, CD34, and CD61. Because of the absence of the markers of T-cell, B-cell, and myeloid lineage-specific antigens, we added CD16/56 for the immunophenotyping and the blasts were positive (94%). The tumor cells of biopsied lymph node were only positive for CD56, consistent with NK cell lymphoma. Epstein-Barr virus (EBV) was not detected by RNA in situ hybridization. Culture for M. tuberculosis was negative. Thus this patient was diagnosed with blastic NK cell lymphoma/leukemia involving bone marrow and lymph node.
authors: Department of Laboratory Medicine, Catholic University Hospital of Daegu, Nam-Gu, Daegu, Korea.
authors: A Jin
authors: AJ
authors: Lee
authors: Sang Gyung
authors: SG
authors: Kim
authors: Chang Ho
authors: CH
authors: Jeon
authors: Hun Suk
authors: HS
authors: Suh
authors: Ghil Suk
authors: GS
authors: Yoon
authors: An Na
authors: AN
authors: Seo
mesh_terms: D001853:Bone Marrow / Q000473:pathology; D005260:Female; D006684:HLA-DR Antigens / Q000378:metabolism; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology / Q000473:pathology*; D007938:Leukemia / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008875:Middle Aged; D014388:Tuberculosis, Lymph Node / Q000175:diagnosis
chemical_list: D006684:HLA-DR Antigens; D017493:Leukocyte Common Antigens