In patients with unexplained arterial
embolism or unexplained cerebral vascular accidents, a diagnosis of
paradoxical embolism should be taken into consideration. It consists in the passage of an
embolus, originating in the venous system or the right side of the heart, via an abnormal right to left channel, into the systemic circulation. In the majority of cases the abnormal communication is a
patent foramen ovale; its incidence varies from 6% to 29% in unselected autopsies. The diagnosis of
paradoxical embolism requires the presence of four Johnson's criteria. Nowadays the diagnostic procedures have been simplified by introducing non-invasive techniques based on ultrasound evaluation. The treatment of
paradoxical embolism must be individualized and consists above all in the use of
anticoagulants. Here we report a case of right leg
paradoxical embolism in a young woman who had been operated on three months earlier for
breast cancer. After ilio-femoro-popliteal thromboembolectomy, Doppler of the lower limb veins was performed. The presence of iliac
venous thrombosis led to a suspicion of
paradoxical embolism, which was then confirmed by the demonstration of a
patent foramen ovale. The diagnosis of
paradoxical embolism is important because the condition is associated with significant morbidity and mortality rates.