European Journal of Echocardiography 2006 7(1):62-66; doi:10.1016/j.euje.2005.02.004
Copyright © 2005, The European Society of Cardiology
Intracardiac pseudotumor caused by mitral annular calcification
E.A. de Vreya,*,
A.J.H.A. Scholtea,
X.H. Kraussa,
R.A. Dionb,
D. Poldermansc,
E.E. van der Walla and
J.J. Baxa
aDepartment of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
bDepartment of Thoracic Surgery, Leiden University Medical Center, Leiden, The Netherlands
cDepartment of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands
Received 29 September 2004; accepted after revision 12 February 2005.
* Corresponding author. Tel.: +31 71 5283944. e.a.de_vrey{at}lumc.nl
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Abstract
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The current report describes a rare case of a pseudotumor in
the left ventricle. Transthoracic and transesophageal echocardiography
demonstrated a round, echodense, mobile mass attached to the
posterior mitral leaflet and annulus. At surgical exploration
caseous annular calcification of the posterior mitral leaflet
was diagnosed. After resection of the mass, successful mitral
valvular plasty was performed. Review of the literature indicated
that mitral annular calcification is associated with an increased
risk of stroke. Optimal treatment may be surgery, especially
when valve plasty can be performed, although randomized trials
are currently lacking.
Keywords: Intracardiac masses; Echocardiography; Mitral annular calcification
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1 Case report
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A 61-year-old man was admitted to the hospital for further evaluation
of an intracardiac mass detected at echocardiography in a referring
hospital. The medical history consisted of hypertension, hypercholesterolemia,
obesity and diabetes mellitus type 2 with secondary renal dysfunction.
At presentation, he complained of mild shortness of breath at
exercise and claudication. At physical examination, no abnormalities
were observed apart from obesity. Laboratory measurements were
normal except elevated serum creatinine (288 mmol/l).
Transthoracic echocardiography was performed (Fig. 1) which showed a round, echodense mass in the left ventricle, attached to the posterior mitral leaflet. There was minimal mitral regurgitation without stenosis. There was left ventricular hypertrophy with normal LV dimensions (LVEDD 55 mm, LVESD 35 mm) and normal function (FS 38%, biplane LVEF 58%). Transesophageal echocardiography demonstrated a round, lobulated, inhomogeneous echodense, partly mobile, mass of 2x3 cm, attached to the posterior mitral annulus (Fig. 2). Furthermore, protrusion of the tumor into the left atrium was observed. The subvalvular mitral apparatus was intact. Left atrial appendage showed no thrombus.
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Figure 1 Transthoracic long-axis view demonstrating a tumor-like structure, 2x3 cm, attached to the posterior mitral leaflet of annulus (arrow). LA, left atrium; LV, left ventricle; RV, right ventricle; Ao, aorta.
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Based on the size, mobility and location of the mass, the risk
of embolization in this patient was estimated high. The tumor
was considered to be either a myxoma or caseous mitral annular
calcification. The patient was accordingly scheduled for surgery.
Because of age and multiple risk factors for atherosclerosis,
coronary angiography was performed preoperatively. No significant
coronary artery disease was revealed.
During surgery, a large calcified atheroma cyst was observed, originating from the posterior mitral annulus at level P2 with extension to the left atrial and ventricular wall, filled with caseous material (Fig. 3). After detachment of the posterior leaflet, the mass was removed together with the corresponding segment of P2. The posterior leaflet was reconstructed and reattached to the annulus by means of a sliding plasty. A Physio-ring size 32 was then implanted to reform the annulus (Fig. 4). Histopathology confirmed degenerative atheroma and extensive calcium deposit with some fresh thrombotic material (Fig. 5). No granulocytic infiltrates were observed, some giant cells were seen. Cultures were negative.
During echocardiographic follow-up after surgery (transesophageal
echocardiography directly postoperative, transthoracic after
1 week, 2 months and 8 months), mitral valve anatomy and function
were normal. The patient had an uncomplicated postoperative
course and was discharged in stable condition.
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2 Discussion
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Intracardiac masses often are an incidental finding by echocardiography.
Differential diagnosis of left-sided masses includes thrombus,
vegetation or tumor, most often myxoma. This report presents
a case of an incidental finding by echocardiography of a left
sided intracardiac mass caused by massive mitral annular calcification.
Mitral annular calcification is a chronic, degenerative process of the mitral valve fibrous ring, primarily involving the posterior annulus. It is an expression of atherosclerosis, with identical risk factors as cardiovascular disease.1,2 Mitral annular calcification is observed at autopsy in 3–8% of the population3 and rarely (0.6%) has a large atherosclerotic burden with central "caseous" necrosis resembling a tumor. The incidence of this finding is 0.6% in patients with mitral annular calcification.4
Transthoracic echocardiography provides an excellent noninvasive diagnostic technique for detection of intracardiac masses.5,6 However, in some patients, limited acoustic viewing restricts diagnostic accuracy. Transthoracic ultrasound images (Fig. 1) of this patient were of insufficient quality to adequately assess the origin and composition of the mass. The transesophageal approach has additional value since it improves visualization of cardiac structures, particularly if located posteriorly. Moreover, transesophageal echocardiography has been demonstrated superior in assessing intracardiac origin of a mass, consistence and mobility.5 Echographic differential diagnosis of the mass in this patient included primary or secondary cardiac tumor, vegetation, calcified thrombus, and extensive mitral annular calcification. The most common intracardiac tumor is a thrombus, but the density of the mass in the current patient suggested calcifications. In the absence of mitral valve regurgitation, fever, positive blood cultures or infectious laboratory examinations, valvular endocarditis was unlikely. Clinical signs of malignancy were absent. The most likely diagnosis was either myxoma or caseous mitral annular calcification. The echodense round, lobular aspect and the mobility of the mass were characteristics favoring the diagnosis of myxoma, although myxomas seldom originate from valves. Despite adequate preoperative imaging, final diagnosis in this patient required surgical exploration and histologic confirmation.
Massive mitral annular calcification is relatively rare and can easily be mistaken for tumor or thrombus.7,8 Specific echocardiographic features of caseous mitral annular calcification favor the diagnosis: a large, round echodense, mass in the posterior periannular mitral region, inhomogeneous with central echolucent areas of necrosis. Although mitral annular calcification is often an incidental finding, it has been associated with complications. Rarely, mitral annular calcification is complicated by secondary infection, arrhythmias, mitral regurgitation or stenosis. Several studies have demonstrated an association between mitral annular calcification and stroke.9–11 In particular, mitral annular calcification is detected by echocardiography in 25% of patients with stroke.12 Moreover, Benjamin et al. followed 160 individuals with mitral annular calcification over 8 years in the Framingham cohort.12 Stroke occurred in 13.8% of patients with mitral annular calcification as compared to 5.1% in the control group. After adjustment of risk factors for cerebrovascular disease, a relative risk of 2.1 to develop stroke was demonstrated.
The mechanism for stroke is unclear. Stein et al. and Malaterre et al. demonstrated thrombus formation on mitral annular calcification with embolization of thrombus.10,11 Embolization of small calcified parts of mitral annular calcification is another possible mechanism. Thus, based on the relatively increased risk of embolization, surgery may be the preferred treatment option, especially if the valve can be repaired. Harpaz et al. however, followed 13 patients with mitral annular calcification and caseous necrosis over 3.8 years; all patients were treated conservatively and stroke did not occur in any of the patients.4
Based on these scarce data in the literature, there appears currently no consensus on the optimal treatment of caseous mitral annular calcification, and further studies are needed to resolve this issue.
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3 Conclusion
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In conclusion, a calcified tumor connected to the posterior
mitral annulus should raise suspicion of a pseudotumor caused
by mitral annular calcification. Although the available data
in the literature indicate that mitral annular calcification
is associated with an increased risk of stroke, the optimal
treatment (conservative or surgical) remains to be established.
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References
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- Adler Y., Fink N., Spector D., Wiser I., Sagie A. Mitral annulus calcification – a window to diffuse atherosclerosis of the vascular system. Atherosclerosis (2001) 155:1–8.[CrossRef][ISI][Medline]
- Fox C.S., Vasan R.S., Parise H., Levy D., O'Donell C.J., D'Augostino R.B., et al. Mitral annular calcification predicts cardiovascular morbidity and mortality. The Framingham Heart study. Circulation (2003) 107:1492–1496.[Abstract/Free Full Text]
- Pomerance A. Pathological and clinical study of calcification of the mitral valve ring. J Clin Pathol (1970) 23:354–361.[Abstract/Free Full Text]
- Harpaz D., Auerbach I., Vered Z., Motro M., Tobar A., Rosenblatt S. Caseous calcification of the mitral annulus: a neglected, unrecognised diagnosis. J Am Soc Echocardiogr (2001) 14:825–831.[CrossRef][ISI][Medline]
- Mügge A., Daniel W.G., Haverich A., Lichtlen P.R. Diagnosis of non-infective cardiac mass lesion by two-dimensional echocardiography. Circulation (1991) 83:70–78.[Abstract/Free Full Text]
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- Giannoccaro P.J., Ascah K.J., Chan K.L., Walley V.M. Left atrial mass produced by extensive mitral annular calcification. J Am Soc Echocardiogr (1991) 4:619–622.[Medline]
- Teja K., Gibson R.S., Nolan S.P. Atrial extension of mitral annular calcification mimicking intracardiac tumor. Clin Cardiol (1987) 10:546–548.[ISI][Medline]
- Benjamin E.J., Plehn J.F., D'Agostino R.B., Belanger A.J., Comai K., Fuller D.L., et al. Mitral annular calcification and the risk of stroke in an elderly cohort. N Engl J Med (1992) 327:374–379.[Abstract]
- Malaterre H.R., Habib G., Leude E., Malmejac C., Vaillant A., Djiane. Embolic thrombus on mitral annulus calcification. J Am Soc Echocardiogr (1996) 9:894–896.[CrossRef][Medline]
- Stein J.H., Soble J.S. Thrombus associated with mitral valve calcification. A possible mechanism for embolic stroke. Stroke (1995) 26:1697–1699.[Abstract/Free Full Text]
- Jesperson C.M., Egeblad H. Mitral annulus calcification and embolism. Acta Med Scand (1987) 222:37–41.[ISI][Medline]
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1 Case report
