[Hydatid cyst of the interventricular septum. Apropos of a case].

A cardiac tumour of the interventricular septum was detected in a young woman presenting with an ejectional systolic murmur. Surgical ablation was carried out before a precise diagnosis was made. Histopathological analysis of the surgical specimen confirmed a hydatid cyst. The main complication was complete atrioventricular block. This case underlines the difficulty of making the diagnosis of intracardiac hydatid disease in a non-specific context, because of the long period of clinical latency, despite the considerable aid of echocardiography and other medical imaging techniques (CT scan and magnetic resonance imaging.