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Int J Clin Exp Pathol 2011;4(2):183-189

Case Report
Hairy cell leukemia and variant in Taiwan: report of a variant case and literature review

Yen-Chuan Hsieh, Shen-Tsung Chang, Shih-Sung Chuang, Chin-Li Lu, Chao-Jung Tsao, Ching-Nan Lin, Chin-Yang Li

Departments of Pathology and Medical Research, Chi-Mei Medical Center, Tainan, Taiwan; Departments of Pathology, Taipei Medical
University, Taipei, Taiwan; Division of Hemato-Oncology, Department of Internal Medicine, Chi-Mei Liouying Hospital, Tainan, Taiwan; Mayo
Clinic and Mayo Medical School, Rochester, MN, USA.

Received December 19, 2010; accepted December 29, 2010; Epub January 5, 2011; published February 1, 2011

Abstract: Hairy cell leukemia (HCL) is characterized by leukemic cells with abundant “hairy” cytoplasm, strong cytoplasmic positivity for tartrate-
resistant acid phosphatase (TRAP), characteristic immunophenotype and sensitivity to treatment with purine nucleoside analogs. HCL-variant
(HCL-v) encompasses chronic B-cell leukemias resembling classical HCL but exhibiting variant cytomorphology, variant immunophenotype
and resistance to conventional HCL therapy. We present the case of a 67-year-old Taiwanese male with HCL-v who had leukocytosis and
splenomegaly. His hairy leukemic cells were weakly positive for TRAP and expressed CD11c and CD103 but not CD25. He received oral
chemotherapy with chlorambucil and in complete hematological remission in 9 months but relapsed 2 months later. Literature review revealed
9 cases of HCL and 3 cases of HCL-v including current case from Taiwan. All patients were adults with splenomegaly. The HCL patients had a
significantly higher frequency of leukopenia (p = 0.024) and monocytopenia (p = 0.008) and a lower frequency of leukocytosis (p = 0.018) than
HCL-v patients. All 8 HCL patients responded favorably to 2-chlorodeoxyadenosine with or without splenectomy. The 3 HCL-v patients had
leukocytosis and received chemotherapy with variable outcome. HCL and HCL-v are rare in Taiwan and their pathological and
immunophenotypical features were not fully characterized. A multi-modality approach incorporating hematological findings, cytomorphology,
histopathology, cytochemistry, complete immunophenotyping and clinical features is needed to identify and characterize such cases in Taiwan.

Keywords: CD11c, CD25, CD103, hairy cell leukemia, hairy cell leukemia variant, Taiwan

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Address all correspondence to:
Ching-Nan Lin, MD or Shih-Sung Chuang, MD
Department of Pathology, Chi-Mei Medical Center. 901
Chuang Hwa Road, Yung-Kang, Tainan 710, Taiwan.
Tel: 886-6-2812811 ext. 53683 (CNL) or 53686 (SSC); Fax: 886-6-2511235
cnlin@mail.chimei.org.tw (CNL) or cmh5301@mail.chimei.org.tw (SSC)