However, the clinical data in association with morphological and immunophenotyping data made it possible to safely rule out diagnoses of hairy-cell leukemia (absence of pancytopenia, no cells with the classical morphology of “hairy cell” and immunophenotyping not characterized by strong expression of CD11c, CD25, CD103 and CD123 antigens) or hairy-cell leukemia variant (no lymphocytes with morphology characterized by the presence of central vesicular nucleolus, cytoplasm similar to hairy cell and absence of strong expression of CD11c and CD20 antigens). Here, MS4A1 is linked to hairy cell leukemia.