Ann Thorac Surg 2006;82:2296-2298
© 2006 The Society of Thoracic Surgeons
Case Reports
Cystic Formation of the Foramen Ovale Mimicking a Right Atrial Myxoma
Gernot Seebacher, MDa,
Thomas Binder, MDb,
Herbert Frank, MDb,
Ernst Wolner, MDa,
Werner Mohl, MD, PhDa,*
a Department of Cardiothoracic Surgery, Medical University of Vienna, Vienna, Austria
b Department of Internal Medicine II, Cardiology, Medical University of Vienna, Vienna, Austria
Accepted for publication April 14, 2006.
* Address correspondence to Dr Mohl, Department of Cardiothoracic Surgery, Medical University of Vienna, Währinger Gürtel 18-20, Vienna, A-1090 Austria. (Email: werner.mohl{at}meduniwien.ac.at).
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Abstract
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A 65-year-old woman presented with shortness of breath, stenocardia, and tachycardia. She underwent several steps of examination. Echocardiography showed a suspicious formation in the right atrium extending into the inferior caval vein. The lesion was suspicious for a myxoma, a thrombus, or a malformation. Intraoperatively this formation presented as a cystic formation connected to the right atrial wall in the area of the foramen secundum and filled with blood and five calcified thrombi. We hypothesize that a slit-like opening in the foramen ovale produced a valve-like mechanism bulging parts of the septum secundum and produced this cystic formation.
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Introduction
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Atrial masses represent a variety of different causes [1]. We present the first report in the scientific literature of an unusual tumorous formation of the foramen ovale, filled with blood and five calcified thrombi and reaching into the inferior caval vein.
A 65-year-old woman presented with dyspnea, New York Heart Association functional class II, angina, and tachycardia. A right atrial mass was suspected on transthoracic echocardiography.
A transesophageal echocardiogram showed an echolucent cystic tumor located in the right atrium (4.4 x 2 cm) in close proximity to the inferior vena cava (Fig 1). Color Doppler showed no flow within the cystic formation; however, mild inflow obstruction of the vena cava was present.
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Fig 1. Transesophageal echography of the cystic formation. (AV = aortic valve; IVC = inferior vena cava; LA = left atrium; PA = pulmonary artery; RA = right atrium; TU = tumor.)
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A computed tomographic angiogram of the thorax demonstrated a smooth surface of the mass, which was in continuity with the interatrial septum.
A magnetic resonance image was performed to give further detail on the mass in the sense of mobility, its connection to the right atrium, and structure (Fig 2). The sequence suggested blood flow within the mass and showed increased mobility prolapsing through the tricuspid valve during each cardiac cycle.
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Fig 2. Magnetic resonance image of the heart in (A) axial, (B) coronal, (C) sagittal, and (D) coronal fast field echo sequence (arrows showing the mass).
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At surgery a smooth cystic tumor was found connected to the fossa ovalis with a narrow pedunculus. The tumor consisted of a thin sack that was filled with blood and contained three calcified thrombi (Figs 3A,
3B).
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Fig 3. Surgical specimen: (A) together with two calcified thrombi found inside, and (B) a look inside the cyst.
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Histology of the tumor sack showed a vascularized fibrous wall, with few muscle cells, fatty tissue, and areas of calcification, but no cellular abnormalities. The interior was covered with endothelium (positive staining for factor VIII).
The patient’s postoperative course was uneventful. There was no recurrence within 3 years.
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Comment
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Operative Procedure
This case describes an unusual cystic tumor of the right atrium that shows no coincidence within the published literature [1–6]. Aneurysms of the atrial septum have been reported previously; however an atrial structure mimicking a "gallbladder like aneurysmatic formation" with a small entrance has not been reported before [4–6].
As soon as the small cystic hilus allowed only a one-way passage for blood, the cyst enlarged producing symptoms because of the stasis within the continuously enlarging structure and several thrombi became calcified. During surgery this large sack full of blood obstructed most of the atrium and could only be visualized in toto after incision and drainage of the blood. The sack was then removed together with the pedicle and part of the septum showing a tiny entrance into the saccular tumor from the left atrial side. Closure of the septum was performed by patch closure.
Analysis
Common diagnostic approaches were informative; however exact diagnosis could be made by the surgical procedure and histology only.
Echocardiography showed the highest specificity in the diagnosis, whereas the accuracy of the computed tomographic scan, coronary angiogram, and magnetic resonance imaging of the heart was low. The determinations of whether this finding was of congenital origin or whether it was acquired could not be clarified.
Our hypothesis is that a valve-like entrance in a layer of the septum secundum produced a gradually enlarging balloon-like structure filled with blood. Temporal occlusions of the entrance with subsequent thrombosis and reopening of the entrance producing several partially resorbed sequester gradually transformed into calcifications.
We conclude that this cystic formation was an aneurysmatic formation of part of the septum secundum with a pinhole opening. The blood cycling within this structure formed this gallbladder-like structure and the calcified thrombi within.
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References
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Abstract
Introduction
