Rare occurrence of hairy cell leukemia in the thai population: A case report

Abstract

Hairy cell leukemia (HCL) has been mainly reported from the Western countries. Herein we describe a case of HCL diagnosed in a Thai patient. A 36-year-old man presented with abdominal discomfort, frequent gum bleeding and significant weight loss for 2 months. Physical examination revealed moderate anemia, petechial hemorrhage on the extremities and an enlarged spleen down to the umbilicus. No hepatomegaly or lymphadenopathy was detected. Complete blood counts revealed a hemoglobin (Hb) of 6.6 g/dL, a white blood cell (WBC) count of 1.6×109/L (neutrophil 16%, lymphocyte 71%, monocyte 11%, atypical lymphocyte 1%), and a platelet (PLT) count of 17×109/L. Abnormal large mononuclear cells with villous projections were seen in the blood smear. Although bone marrow (BM) aspiration resulted in a dry tap, abnormal lymphocytes with villous projections could again be identified in the touch preparation. Flow cytometric analysis showed a distinct population above the normal lymphocyte region on CD45/SSC gates with a strong expression of CD19, CD20, CD22, CD25, CD11c, and kappa. CD5, CD23, CD10, CD4, and CD8 were all negative. BM biopsy was consistent with HCL. The patient was treated with splenectomy followed by 8 cycles of fludarabine and cyclophosphamide chemotherapy. At 21 months after diagnosis, the patient was doing well with a Hb of 16.9 g/dl, a WBC count of 6.8×109/L, neutrophil 49.9%, lymphocyte 39.6%, monocyte 8.6%, and a PLT count of 329×109/L). No abnormal lymphoid cells were detected in the blood smear. This present report represents the first Thai HCL case that was immunophenotypically confirmed by flow cytometry and successfully treated at Siriraj Hospital.