[Right intra-atrial extension of hydatid cyst mimicking cardiac thrombosis. Apropos of a case].

The authors describe an unusual case of hydatid cyst inserted in the inferior vena cava and extending into the right atrium. The transoesoesophageal echocardiographic appearances were similar to those of a thrombus: the tumour was very mobile, echogenic, polylobular with a cord-like pedicle in the inferior vena cava. The pathological examination revealed a ruptured hydatid cyst. The mass and its insertion were not visible on CT scan or cavography. Transoesophageal echocardiography would therefore seem to be a very useful diagnostic method for tumours arising in the inferior vena cava and extending into the right atrium.