#00012540

A72-year-old male with a history of increasing dyspnea and weight loss underwent a chest X-ray that revealed a pulmonary mass and thus he was seen by pulmonary service for bronchoscopy. However, routine blood count showed a platelet count of 35x 109/L with a normal hemoglobin and white blood cell count. He was referred to hematology for evaluation of thrombocytopenia. Physical examination was unremarkable. A repeat platelet count was 32 x_ 109/L. Review of the peripheral smear disclosed numerous platelets surrounding the granulocytes consistent with platelet satellitism (see figure) causing pseudothrombocytopenia. He underwent bronchoscopy without complications. Spurious thrombocytopenia is a problem in clinical practice that may sometimes lead to unnecessary evaluations and treatment. Platelet satellitism, which is an in vitro phenomenon, is associated with EDTA-treated blood at room temperature. It is seen in patients with vasculitis, lupus, mantle cell lymphoma, and marginal zone B