Inflammatory myofibroblastic tumors (IMTs) represent mesenchymal tumors that occur in the lungs, abdomen, or pelvis. Cardiac IMTs are rare, usually right-sided, and when left-sided can cause sudden cardiac death by coronary occlusion. We report a child with symptoms of embolization to the right kidney and the femoral artery, and a mobile mass in the left atrium attached to the mitral valve. Upon surgical removal, histopathology revealed IMT. Our case illustrates a unique presentation of systemic thromboembolism.