Ann Thorac Surg 2005;80:737-739
© 2005 The Society of Thoracic Surgeons
Case report
Surgical Treatment of Intramyocardial Foregut Cysts
Richard Curran, MBBS
a
,
Hugh S. Paterson, FRACS
b
,
*
a Department of Cardiothoracic Surgery, Westmead Hospital, Westmead, Australia
b Department of Surgery, University of Sydney, Sydney, New South Wales, Australia
Accepted for publication February 10, 2004.
* Address reprint requests to Dr Paterson, Suite 10, Westmead Private Hospital, 14B Mons Rd, Westmead, NSW 2145, Australia (Email: patersonh{at}aol.com).
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Abstract
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Intramyocardial foregut cysts have been identified as incidental findings at autopsies, but there have been no reports of surgical management of clinically significant cysts. We report 2 patients and provide recommendations for appropriate management.
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Introduction
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Foregut cysts have been described in a variety of locations in the mediastinum. They arise from embryonic remnants of the primitive foregut and include bronchogenic cysts arising from the ventral foregut and enterogenous cysts arising from the dorsal foregut. The majority of these cysts are managed with early surgical resection (1) to obtain tissue diagnosis and (2) to prevent complications related to their enlargement. We report 2 cases of intramyocardial foregut cysts occurring across the atrioventricular groove in close proximity to the posterior mitral annulus. Surgical drainage was undertaken in both cases during cardiopulmonary bypass initiated for coronary artery bypass surgery.
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Case report
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Case 1
A 79-year-old woman was admitted to our hospital with known ischemic heart disease for which she had taken antianginal therapy for the previous 4 years. She also reported recent orthopnea and paroxysmal nocturnal dyspnea. There had been associated episodes of pulmonary edema, and she had been experiencing gradually worsening angina with deterioration in exercise tolerance. She was also known to have a slowly growing intracardiac mass in the left atrioventricular groove.
Six months before this presentation, she had undergone coronary angiography, which showed triple vessel disease with good left ventricular function, moderate mitral incompetence, and a radiopaque mass in the left atrioventricular groove (Fig 1). Echocardiography demonstrated a 5 cm x 4 cm x 3 cm solid cardiac tumor adjacent to the posterior mitral annulus with moderate mitral regurgitation. The mass caused some flow disturbance but no significant mitral stenosis.
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Fig 1. A left ventriculogram (case 1) in a right anterior oblique view shows a radiopaque mass in the posterior atrioventricular groove. There is mitral incompetence.
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The patient underwent coronary artery bypass grafting at which time prebypass transesophageal echocardiography (TEE) confirmed the echogenic mass adjacent to the posterior mitral annulus (Fig 2) with minimal mitral incompetence. There was a palpable mass in the posterobasal aspect of the left ventricle. This mass was evident on opening the left atrium, with ulceration of the overlying endocardium. An attempt to take a biopsy sample of the tumor resulted in extrusion of the cyst contents, which consisted of necrotic material that had a pasty yellowish-gray appearance. The contents were evacuated, and the cyst wall closed from within the left atrium. There was no plane of dissection that would allow removal of the cyst.
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Fig 2. Transesophageal echocardiography (case 1) demonstrates the echogenic mass adjacent to the mitral valve. (LA = left atrium; LV = left ventricle.)
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After completion of the coronary bypass grafting, the heart separated from cardiopulmonary bypass (CPB) satisfactorily but with high pulmonary artery pressures. TEE demonstrated severe mitral incompetence. On reopening the left atriotomy, it was apparent that the cyst had become distended and was distorting the posterior mitral annulus. We elected to replace the morphologically normal mitral valve with a 25-mm bioprosthesis in this small patient. Separation from CPB was achieved with an intraaortic balloon pump and inotrope support, but the patient subsequently died of low cardiac output. It is likely that bleeding into the closed cyst cavity after evacuation of all the contents not only distorted the mitral annulus but also resulted in splinting of the left ventricular wall.
At autopsy, sections of the cyst wall showed dense fibrous tissue with areas of calcification. No epithelial lining was identified. There was no evidence of malignancy. It was presumed to be a developmental cyst showing degenerative changes and calcification. The cyst contents showed basophilic material in which there were fragments of calcified crystalline material.
Case 2
A 63-year-old woman was admitted to our hospital with a recent history of unstable angina. Coronary angiography showed triple vessel disease with normal left ventricular function. A calcified mass was noted adjacent the posterior mitral annulus (Fig 3). This was confirmed by echocardiography.
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Fig 3. A left coronary angiogram in a right anterior oblique view (case 2) shows the radiopaque mass crossing the atrioventricular groove. (Cx = circumflex artery; LAD = left anterior descending artery.)
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She underwent coronary artery bypass surgery at which time prebypass TEE demonstrated a competent and normally functioning mitral valve. There was a mass visible from within the left atrium beneath the endocardium and extending across the atrioventricular groove behind the posteromedial portion of the mitral annu lus. On incising the endocardium, gray sebaceous-type material extruded from the cyst. There was no plane of dissection outside the cyst. The mass was also palpable within the left ventricular wall posteriorly.
In view of the experience with the first patient, no attempt was made to evacuate the cyst contents via the left atriotomy. The cyst wall was closed, and the cyst was then entered posteriorly through the free wall of the left ventricle adjacent to the atrioventricular groove. A cruciate incision was made with extrusion of the sebaceous-type material.
After completion of the coronary artery bypass grafting, the heart separated from CPB without support. Postoperative recovery was uneventful.
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Comment
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Cysts of the myocardium are very uncommon. When they occur, they are most commonly hydatid cysts. Myocardial involvement occurs in less than 2% of hydatid disease [1]. Hydatid cysts in the heart usually shell out from the surrounding myocardium relatively easily.
Although a positive histologic diagnosis could not be made in either of these cases, the findings are typical of degenerate foregut cysts. In case 1, the cyst wall was fibrous and calcified with no epithelial lining identified. In case 2, no attempt was made to excise or obtain a biopsy specimen of the cyst wall. Both cysts contained necrotic sebaceous-type material with calcification typical of foregut cysts [2].
Foregut cysts more commonly occur in the mediastinum where the natural history is one of enlargement and compression of surrounding structures due to infection, epithelial secretions, or bleeding. Two thirds of patients eventually develop symptoms, usually due to airway obstruction [2].
In a series of 444 adult autopsies with a primary tumor or cyst of the heart or pericardium, 6 patients had an intramyocardial bronchogenic cyst [3]. These were the only intramyocardial cysts; they were 1 to 2 cm in diameter and were incidental findings. One of the six cysts crossed the posterior atrioventricular groove as in our 2 patients. In the same series, there were 80 simple pericardial cysts and 118 myxomas.
Shelling out of these rare foregut cysts may not be possible because the cyst wall may degenerate to a thin, fibrous capsule intimate with the adjacent myocardium. The size of the cyst may also preclude cyst removal due to disruption of ventricular or valve function, depending on the location. In this circumstance, decompression by drainage may be the most judicious management.
Because these cysts are rare, there is an inclination to obtain a tissue diagnosis at the time of cardiac surgery. There is a reluctance to leave the cyst cavity communicating with a cardiac chamber, and so it is recommended that the cysts be drained into the pericardium. Aggressive evacuation of the contents does not appear necessary and may cause bleeding from the cyst wall. The presence of radiopaque material within the cyst should distinguish it from other types of cysts so that it is reasonable to make a positive diagnosis without tissue confirmation.
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References
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- Miralles A, Bracamonte L, Pavie L, et al. Cardiac echinococcosisSurgical treatment and results. J Thorac Cardiovasc Surg 1994;107:184-190.[Abstract/Free Full Text]
- Strollo D, Rosado-de-Christenson ML, Jett JR. Primary mediastinal tumors: part IITumors of the middle and posterior mediastinum. Chest 1997;112(5):1344-1356.[Abstract/Free Full Text]
- McAllister HA, Fenoglio JJ. Tumors of the cardiovascular systemIn: Hartman WH, Cowan WR, editors. Atlas of tumor pathology. Fascicle 15, second series. Washington, DC: Armed Forces Institute of Pathology; 1978. pp. 1-64.
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Abstract
Introduction
