Pure Biclonal Hairy Cell Leukemia–Apt Diagnosis with Multicolor Flow Cytometry

Hairy cell leukemia (HCL) is a rare B-cell neoplasm that constitutes around 2 percent of all lymphoid leukemias and occurs more frequently in elderly males. The usual triad of HCL includes pancytopenia, splenomegaly, and hairy cells in the bone marrow. This is a case of an atypical presentation of biclonal HCL diagnosed on flow cytometry; the existence of biclonal HCL is extremely rare with very few case reports. Pure biclonal HCL should be regarded as an extraordinary finding among the so-called composite lymphomas.