Yonsei Medical Journal Vol. 46, No. 3, pp. 439 - 444, 2005 Primary Idiopathic Chylopericardium Associated with Cervicomediastinal Cystic Hygroma Byoung Chul Cho1, Seok-Min Kang1, Seung Chul Lee1, Jeong Geun Moon1, Dong Hyung Lee1, and Sang Hyun Lim2 1Cardiology Division, Cardiovascular Research Institute, 2Department of Thoracic and Cardiovascular Surgery, Yonsei University College of Medicine, Seoul, Korea. Chylopericardium is a rare clinical entity in which chylous fluid accumulates in the pericardial cavity. We report a case of primary idiopathic chylopericardium associated with mul- tiple, small cervicomediastinal cystic hygromas occurring in an asymptomatic 43-year-old woman with no history of trauma, thoracic surgery, malignancy, infection or tuberculosis. Echo- cardiography showed a large amount of pericardial effusions and pericardial fluid analysis revealed inappropriately elevated triglyceride. We did not demonstrate communication between the thoracic duct and the pericardial sac by lymphangiography and chest computed tomography. She successfully responded to 30 days of continuous pericardial drainage and 15 days of a medium-chain triglyceride diet after 30 days of total paren- teral nutrition. Follow-up echocardiography 6 months after treatment commencement showed a minimal reaccumulation of pericardial fluid without symptom. We conclude that if a patient is asymptomatic and can well tolerate daily life, surgery including pericardiectomy or ligation of the thoracic duct is not necessarily required. Key Words: Chylopericardium, pericardial effusions INTRODUCTION The accumulation of chyle in the pericardial cavity, therefore called chylopericardium, is an unusual clinical entity.1 It usually arises from mediastinal neoplasma,2 thrombosis of the subcla- vian vein,3 tuberculosis,4 nonsurgical trauma5 or Received May 27 2004 Accepted August 23, 2004 Reprint address: requests to Dr. Seok-Min Kang, Cardiology Division, Cardiovascular Research Institute, Yonsei University College of Medicine, 134 Sinchon-dong, Seodaemun-gu, Seoul 120-752, Korea. Tel: 82-2-361-7267, Fax: 82-2-393-2041, E-mail: smkang@yumc.yonsei.ac.kr thoracic or cardiac surgery.6,7 Primary idiopathic chylopericardium, which literally means it has no known etiology, is even rarer.8-16 It was first described as clinical entity by Groves and Effler in 1954.8 Although several reviews on the subject have been published, its etiology remains unclari- fied. However, many previously reported cases of primary idiopathic chylopericardium were treated by ligating and resecting the thoracic duct, which suggests that leaks from the thoracic lymphatics resulted in the chylous effusion.8,10,11,13-16 We re- port a case of primary idiopathic chylopericar- dium associated with multiple, small cystic hy- gromas in a 43-year-old woman, which was successfully treated using pericardiostomy, con- comitantly with medium chain triglyceride and low fat meal dietary support after total parenteral nutrition. CASE REPORT A 43-year-old woman was referred to our hospital for cardiomegaly on chest X-ray (Fig. 1). Physical examinations revealed a healthy ap- pearing woman except for distant heart sounds. All laboratory findings were within the normal range. The patient had no history of trauma, congenital heart disease, thoracic surgery or tuber- culosis. Transthoracic echocardiography revealed a large amount of pericardial effusion without hemodynamic compromise. Diagnostic pericardio- centesis was performed with 500 mL of a milky- colored pericardial fluid aspirated. Routine exami- nation of the pericardial fluid revealed pH 6.8, Yonsei Med J Vol. 46, No. 3, 2005