[B-cell non-Hodgkin lymphoma discovery after observation of a platelet satellitism around atypical lymphocytes].

We report the case of an 83-year-old woman admitted to the accident and emergency unit for pneumopathy. The blood cell count on the DXH automaton (Coulter® ™ UniCel® DxH) found a normochromic and normocytic anemia, anormal platelet count and subnormal leukocyte formula. The only alarm raised by the automaton was the presence of a basocytosis. A control of the leucocyte count by flow cytometry and blood smear has been done. It revealed there was no basocytosis, but showed the presence of an atypical monomorphic lymphocytes B population (T/B < 1 ratio in flow cytometry), around which platelets aggregated. The lymphocytic immunophenotyping allowed us to highlight the presence of a CD5+ B clonal subpopulation.