en گزارش مورد Case Report <p>Thrombotic events are very unusual in neonatal period. This congenital anomaly may be caused by certain risk factors such as polycythemia, perinatal asphyxia, septicemia, maternal diabetes, dehydration, and low cardiac output, or it may occur upon catheterization of central lines. A 20-day-old neonate was referred to our ward with primary signs of hypertrophic cardiomyopathy (HCMP). Echocardiography and CT-angiography were performed to find stenosis or no stenosis of aortic valve, which showed a great mass into the ascending aorta. This mass was resected and removed successfully and thereafter the aortic arch was repaired. There was no prothrombic disorder in his family history.</p> Neonatal, Hypertrophic cardiomyopathy, Thrombosis, Echocardiography, Aorta 30 32 http://jsurgery.bums.ac.ir/browse.php?a_code=A-10-54-4&slc_lang=en&sid=1 Mohammad Nasir Hematin nasir.hematian90@yahoo.com 10031947532846002045 10031947532846002045 Yes Atherosclerosis and Coronary Artery research Center, Birjand University of Medical Sciences (BUMS), Birjand, Iran Mahmood Hosseinzadeh-Maleki 10031947532846002046 10031947532846002046 No Birjand CardioVascular Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran Reza Shabanian 10031947532846002047 10031947532846002047 No Assistant Professor of pediatric cardiology, MarkaztebbiKodakan Hospital, Tehran University of Medical Sciences, Tehran, Iran Mohammad Ali Navabi 10031947532846002048 10031947532846002048 No Associate Professor of Cardiac Surgery, MarkaztebbiKodakan Hospital, Tehran University of Medical Sciences, Tehran, Iran Forod Salehi 10031947532846002049 10031947532846002049 No Birjand CardioVascular Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran