The classical triad of sudden devastating chest pain, electrocardiographic absence of acute myocardial infarction, and identification of an upstream flap in the ascending aorta by transesophageal echocardiography (TEE) indicates aortic type A dissection requiring emergent surgery. Among 34 patients presenting with clinical signs and symptoms of an aortic dissection, three did not show the mandatory flap in the upstream aorta. The only echocardiographic finding was aortic wall thickening indicating an intramural hematoma. Two of these patients showed early aortic ectasia and one showed a pericardial effusion. Despite the missing flap echocardiographically, surgery was performed in all three patients. The surgical approach was the same as that for patients with a type A dissection. Two patients are doing well after the procedure, and one patient died after reoperation. The postoperative histologic work-up confirmed that there was no intimal tear or dissection of the intimal layer. We conclude that the echocardiographic finding of an intramural hematoma combined with typical clinical signs of chest pain, with myocardial infarction ruled out, requires emergent surgical intervention.