An 11 day-old female infant underwent resection of a mass in the subaortic region secondary to critical aortic stenosis. At 3 months of age, recurrent severe left-ventricular outflow obstruction (LVOT) in the setting of heart failure prompted redo surgery, and the resected mass revealed an intracardiac foregut cyst, which is a rare finding. To our knowledge, this is the first case describing obstruction of the LVOT.