Hepatosplenic T-cell lymphoma (HSCTL) is rare and caracterised by gama/delta T-lymphocyte proliferation in the spleen, bone marrow and liver. Association between HSCTL and hemophagocytic syndrome is known, but association with chronic lymphoid leukaemia (CLL) has not been described to our knowledge. We report the case of a 76 year's old woman, with untreated CLL, presenting with febrile pancytopenia and splenomegaly. First test revealed a hemophagocytic syndrome without CLL transformation, and with a spontaneous and favorable evolution. Fever and cytopenias recur one month later. We find then a atypical circulating lymphocyte T population, negative for CD4 and CD8. The marrow immuno-phenotyping reveals a T CD4-CD8- gamma/delta lymphoid infiltration, leading to the diagnostic of HSTCL.