An unusual right heart mass.

A mobile right atrial mass, prolapsing into the right ventricle and extending to the inferior vena cava, was unexpectedly discovered during a routine echocardiographic examination in a 53-year- old woman. A possible tumour was suspected, but no evidence of primary malignancy was detected in lungs, liver, kidneys and adrenal glands. The patient underwent surgery, and only histological examination of the mass provided a final diagnosis of thrombosis.