From Bicuspid to Quadricuspid Aortic Valve: The Clinical Case of a 38-year-old Woman with Chest Pain.

We report a case of a 38-year-old woman with an alleged diagnosis of bicuspid aortic valve disease that was correctly identified as quadricuspid aortic valve (QAV) disease in our cardiology unit. In this case report, we focus on echocardiographic features of this rare congenital valve disease aiming to provide useful tips to achieve correct differential diagnosis according to the updated echocardiographic international guidelines and recommendations, briefly reviewing other QAV cases reported in the current literature as well. In conclusion, we strongly recommend adhering to practical echocardiographic guidelines to reduce interobserver variability, not to miss the diagnosis of rare congenital defects like the one we reported.