Hernia of the diaphragmatic caval foramen causing right atrial mass, caval obstruction and pulmonary embolism

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1 Accepted Manuscript Hernia of the diaphragmatic caval foramen causing right atrial mass, caval obstruction and pulmonary embolism Alexis Benitez Lazzarotto, Nicholas A. O Rourke, Benjamin T. Fitzgerald, David Wong, Gregory M. Scalia PII: S (16) DOI: doi: /j.ijcard Reference: IJCA To appear in: International Journal of Cardiology Received date: 7 January 2016 Accepted date: 9 January 2016 Please cite this article as: Lazzarotto Alexis Benitez, O Rourke Nicholas A., Fitzgerald Benjamin T., Wong David, Scalia Gregory M., Hernia of the diaphragmatic caval foramen causing right atrial mass, caval obstruction and pulmonary embolism, International Journal of Cardiology (2016), doi: /j.ijcard This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

2 Title Hernia of the diaphragmatic caval foramen causing right atrial mass, caval obstruction and pulmonary embolism. Authors: Alexis Benitez Lazzarotto - The Wesley Hospital alexis.benitezlazzarotto@gmail.com Nicholas A. O Rourke - The Wesley Hospital orourke.nick@gmail.com Benjamin T Fitzgerald Heart Care Partners bmcd124@yahoo.com.au David Wong - Wesley Medical Imaging dcwong@iprimus.com.au Gregory M Scalia. Heart Care Partners / University of Queensland Keywords: gmscalia@gmail.com (corresponding Author) Cardiac Mass Vena Cava Hernia Diaphragm

3 The following case report will discuss a rare cardiac mass that was discovered through routine echocardiogram follow up for a patient with known cardiomyopathy. Whilst myxomas, metastatic tumors, vegetations and thrombi are the usual suspects, a far less common phenomena was observed herewith. A 66 year old male with a background history of moderate idiopathic cardiomyopathy, recurrent atrial fibrillation, minor coronary atherosclerosis and obesity, presented asymptomatically for a routine follow-up echocardiogram. The left ventricle was mildly dilated and the wall mildly thickened with preserved systolic function (Simpson's ejection fraction 67%, grade 2 diastolic dysfunction). The right ventricle was normal in size and systolic function. The left atrium was moderately dilated and the right atrium (RA) was mildly dilated. All four cardiac valves were normal. A large (3cm diameter), spherical, homogenous echogenic mass was noted in the right atrium which appeared to enter from the IVC (see figure 1A and 1B). Color Doppler flow studies indicated that the mass was causing inferior vena cava (IVC) obstruction at the entrance to the right atrium (see figure 1C). The mass contained no blood flow. The mass appeared contiguous with the liver. The cava within the liver was not compressed and had no tissue within it. Thoraco-abdominal computed tomography (CT) revealed complete right diaphragmatic eventration with most of the liver shifted cranially, occupying a significant portion of the right chest cavity (see figure 1D). The right atrial mass had a density consistent with adipose tissue (see figure 1E). This fat tissue had actually prolapsed through a hernia of the caval foramen of the diaphragm,

4 extrinsically compressing the diaphragmatic wall of the right atrium, producing the mass appearance seen by echocardiography. The kidneys had no tumors. Contrast CT venography demonstrated narrowing of the inferior vena cava at its junction with the right atrium. The intra-hepatic and abdominal cava was dilated. Pulmonary arterial phase imaging showed a right upper lobar pulmonary embolus (see figure 1F). Peripheral venous duplex sonography showed no deep vein thrombosis. There were no clinical manifestations of caval obstruction or the pulmonary embolus. The patient was placed on a novel anticoagulant. Hepatic surgical / interventional radiology case review suggested that no percutaneous intervention was feasible to relieve the caval obstruction. The finding of pulmonary embolus however mandated anticoagulation and consideration of some form of surgical intervention. Laparoscopic surgery demonstrated a large tongue of peri-hepatic fat herniating through the caval foramen of the diaphragm. This was dissected off the right crus and sutured to the lesser curve of the stomach. No attempt was made to patch the hernial defect, for fear of increasing the density of the paracaval lesion and possibly distorting the cava further with scarring. The patient underwent en passant repair of a recurrent umbilichal hernia and was discharged well the next day. (see figure 1GSix months duration of anticoagulation was prescribed. Post-operative CT imaging showed complete resolution of the right atrial mass and caval distension (see figure 1H). The incidental finding of a right atrial space occupying lesion (which turned out to be extrinsic), could easily be misdiagnosed and mistreated and in this case had life threatening sequelae pulmonary embolus.

5 Right atrial masses are rare and are most often the results of tumors, thrombi, or vegetations [2]. Tumors are rarely primary (sarcoma and myxoma). Secondary tumors famously spread hematogenously up the inferior vena cava from the kidneys (renal cell carcinoma) or the uterus (fibrolyeomyomatosis). This mass was composed of fat and it should be noted that intracardiac lipomas are very rare being found at a rate of 0.01% in Lam et al s [3] autopsy of 12,000 subjects. Furthermore lipomas only make up 10% of benign cardiac tumors, with malignant tumors comprising 10 to 25% of all primary cardiac tumors [4]. Anatomic abnormalities around the diaphragmatic caval foramen can mechanically distort the junction of the cava and right atrium [1]. Complete eventration of the diaphragm is unusual and less common than partial eventration. Fibrous tissue replaces all or part of the musculature of the diaphragm. Progressive thinning and increased elasticity of the diaphragm allows herniation of abdominal contents. Diagnosis is often made incidentally through chest radiographs as patients are rarely symptomatic with the disorder [5,6]. Whilst surprisingly, there is no reported evidence that obesity increases the incidence of diaphragmatic eventration, it should be noted that increase body mass index and Caucasian decent carry an increased risk of retroxiphoid hernias [7,8]. On echocardiography, the mass did not mobilize in time with cardiac motion, which raised the suspicion that the mass was extrinsic to the heart. This prompted the CT

6 scan which identified the diaphragmatic hernia. In the literature, diaphragmatic hernias have been found to mimic cardiac masses on transthoracic echocardiography [8]. However, most of these masses are described in the left atrium, as it is rare that a hernia travels anteriorly to the mediastinum and affect the right atrium. Thoracic CT imaging provides accurate imaging of diaphragmatic eventration, as well as identifying the tissue characteristics (e.g. omental fat). Sutro et al. [9] suggest that the most important finding for the diagnosis of omental fat herniating through the diaphragm is the presence of radiating fine linear or curvilinear densities, which would suggest the presence of omental blood vessels. In summary, although rare, diaphragmatic hernias can mimic right atrial masses. If an immobile mass is identified by echocardiography, which does not have movement in time with cardiac motion, extrinsic structures should be considered. Thoraco-abdominal imaging with CT has proven useful in delineating the anatomical origin and the tissue characteristics in this case, allowing prompt treatment with surgery and anticoagulation.

7 References [1] Si Hun K, Myoung Gun K, Wook-Jin C, et al., Unusual diaphragmatic hernias mimicking cardiac masses. Journal Of Cardiovascular Ultrasound [serial online]. June 2015;23(2):107. Available from: Publisher Provided Full Text Searching File, Ipswich, MA. Accessed November 18, 2015 [2] Chen M, Sun J, Asher C. A right atrial mass and a pseudomass. Echocardiography [serial online]. May 2005;22(5): p. Available from: CINAHL Plus with Full Text, Ipswich, MA. Accessed November 17, 2015 [3] Lam KY, Dickens P, Chan AC: Tumors of the heart. A 20-year experience with a review of consecutive autopsies. Arch Pathol Lab Med 1993;117: [4] Sharma A, Sidhu R, Paterson D. Right atrial mass in a 23-year-old woman with molar pregnancy. CMAJ [serial online]. 2015:350. Ipswich, MA. Accessed November 17, 2015 [5] Piehler JM, Pairolero PC, Gracey DR, Bernatz PE. Unexplained diaphragmatic paralysis: a harbinger of malignant disease? J. of Thorac Cardiovasc Surg 1982; 84:861. [6] Hart N, Nickol AH, Cramer D, et al. Effect of severe isolated unilateral and bilateral diaphragm weakness on exercise performance. American J. of Res and Crit. Care Med. 2002; 165:1265.

8 [7] M. Okino, K. Yamashita, N. Morita, K. Esato. Laparoscopic repair of a diaphragmatic hernia through the foramen of Morgagni. Surg Endo. 1997; 11(6): [8] L. Wilson, W. Ma and B. Hirschowitz. Association of obesity with hiatal hernia and esophagitis. American J. Gastro. 1999; 94: [9] Nishimura RA, Tajik AJ, Schattenberg TT, Seward JB. Diaphragmatic hernia mimicking an atrial mass: a two-dimensional echocardiographic pitfall. J. of American College of Cardio Apr; 5(4): [10] Sutro WH, King SJ. Computed tomography of Morgagni hernia. NY State J. of Med. 1987;87:

9 Figure 1 Legend. A. Transthoracic 4 chamber view showing large globular mass (arrow) in the right atrium. The mass appears to be originating posteriorly. There was no visible attachment to the interatrial septum. B. Subcostal 4 chamber view showing the mass extending into the right atrium (arrow) from below the diaphragm. The mass appears to be contiguous with the liver. There is compression of the inferior vena cava (IVC) anatomically. C. Colour flow Doppler shows accelerated blood flow from the inferior vena cava into the right atrium consistent with obstruction. D Coronal CT imaging showing fat density tissue prolapsing through the diaphragm (arrow) causing extrinsic compression of the right atrium. E. Axial CT imaging showing fat density globular mass in the right atrium. F. CT pulmonary angiography showing embolism (arrow) in the distal right pulmonary artery. G. Surgical image showing peri-hepatic fat prolapsing through the caval foramen, compressing the inferior vena cava. H. Postoperative coronal CT imaging showing resolution of the herniation through the diaphragm (arrow) with no evidence post-operatively of extrinsic compression of the right atrium.