CD4 and CD8 double‐negative adult T‐cell leukemia/lymphoma with monomorphic cells expressing CD99: A diagnostic challenge in a country non‐endemic for human T‐cell leukemia virus |
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Authors: | Tsung‐Hsien Lin Hung‐Chang Wu Yen‐Chuan Hsieh Chih‐En Tseng Ryo Ichinohasama Shih‐Sung Chuang |
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Affiliation: | 1. Department of Pathology, Chi‐Mei Medical Center;2. Division of Hemato‐Oncology, Department of Internal Medicine, Chi‐Mei Medical Center;3. Department of Medical Laboratory Science and Biotechnology, Chung Hwa University of Medical Technology, , Tainan;4. Department of Anatomic Pathology, Buddhist Dalin Tzu Chi General Hospital, , Chiayi;5. Division of Hematopathology, Tohoku University Graduate School of Medicine, , Sendai, Japan;6. Department of Pathology, Taipei Medical University, , Taipei, Taiwan |
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Abstract: | Adult T‐cell leukemia/lymphoma (ATLL) is a peripheral T‐cell neoplasm caused by human T‐cell lymphotropic virus type I (HTLV‐I). The neoplastic cells are highly pleomorphic and are usually CD4+ and CD8? phenotypically. We reported the case of a 46‐year‐old woman presenting with fever, abdominal distention, lymphadenopathy, leukocytosis and hypercalcemia. Nodal biopsy showed diffuse infiltration by monomorphic small to medium‐sized atypical lymphocytes expressing CD3, CD25, CD30 and CD99, but not CD1a, CD4, CD8, CD34, terminal deoxynucleotidyl transferase or ALK. An initial diagnosis of T‐lymphoblastic leukemia/lymphoma was made based on cytomorphology, CD4 and CD8 double negativity, and the expression of CD99. The diagnosis was later revised to ATLL based on the positive serology study for anti‐HTLV I/II antibody and confirmation by the clonal integration of HTLV‐I proviral DNA into the tumor tissues by Southern blotting analysis. The patient had a stage IVB disease and died of septic shock after 2 courses of chemotherapy 3 months after diagnosis. Immunohistochemical staining for CD99 in archival ATLL tissues showed a positive rate of 67% (4 of 6 tumors). Our case showed that ATLL with atypical morphology and immunophenotype in HTLV non‐endemic areas might pose a diagnostic challenge and CD99 expression is frequent in ATLL. |
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Keywords: | adult T‐cell leukemia/lymphoma CD4 CD8 CD99 human T‐cell lymphotropic virus Taiwan |
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