Granulocytic sarcoma presenting as a right atrial mass

We describe a 48-year-old male who developed acute myelogenous leukaemia (AML) associated with a right atrial mass. The patient was admitted with fatigue, positional dyspnoea and headache. Transthoracic echocardiography (TTE) and transoesophageal echocardiography (TEE) revealed that the right atrium was filled with a mass. Peripheral blood smear revealed 85% blasts, and bone marrow examination showed 74% myeloid blasts and 27% monocytoid cells (monoblast and promonocytes). Immunophenotypic analysis of the bone marrow aspirates showed CD13, CD14 and CD33 positivity, consistent with acute myeloid leukaemia of M4 Fab subtype. The patient achieved remission (but not cure) accompanied by near resolution of the right atrial mass following intensive chemotherapy.