A cavitating cardiac mass may represent various etiologies, the most common being hydatid cyst, myxoma, and thrombus. Diagnosis is crucial as treatment strategies are very different. Although echocardiography is the initial imaging modality for a suspected cardiac mass, it does not allow for accurate tissue characterization. Cardiac magnetic resonance imaging helps to confirm the diagnosis as it incorporates a variety of pulse sequences and assesses the perfusion and delayed enhanced characteristics of the mass and myocardium. Multidetector computed tomography angiography is useful for preoperative demonstration of coronary arteries and tumor vascularity. This report describes a case of cavitating atrial myxoma suspected to be a hydatid cyst on echocardiography. Magnetic resonance imaging and multidetector computed tomography helped in the complete diagnostic workup.