A 49 years old Romanian lady was admitted to the department of infectious diseases because of dyspnoea, malaise and mild fever. Chest X-ray was normal. A 12 lead ECG demonstrated right bundle branch block, and a transthoracic echocardiography showed a mass in the mid inter-ventricular septum, measuring 40x25 mm, protruding into the right ventricular chamber. The mass had the appearance of a solid lesion iso-echoic with the myocardium with hypo-echoic zones inside, resembling a "ball of wool" (Figure 1), suggesting a myxoma. Otherwise, all echocardiographic parameters After excision, the mass appeared encapsulated and measured 3x5 cm. It was filled with gelatinous material which was confirmed to be hydatid cyst.