CASE REPORT

A 73-year-old patient was admitted to the emergency department for an ST-segment elevation myocardial infarction. The patient reported sudden onset of persisting chest pain and dyspnea for three hours. The clinical history of the patient included diabetes, arterial hypertension, and prior stroke in the year 2002. 
Initial 12-lead electrocardiogram showed sinus rhythm with posterior and inferior ST-segment elevation. The transthoracic echocardiography revealed inferior and lateral hypokinesia of the left ventricle. Moreover, a large, echo-dense mass with central echolucency and well-defined calcified margins was detectable. 
Emergency coronary angiography via transradial approach revealed a thrombus in the proximal left circumflex artery. Except for the proximal embolic occlusion, adequate blood flow was detectable in the distal artery. Furthermore, the coronary arteries were free of atheromatous lesions. After thrombus resolution with heparin and tirofiban, recovery of ST segment elevation and improvement in clinical symptoms were observed.
Diagnostic work-up for differentiation of the cardiac tumor included transesophageal echocardiography, that showed a well-circumscribed, smooth-bordered echo-dense mass (2.9 x 1.9 cm) at the posterior peri-annular region of the mitral valve, containing central echolucency and suspicious for a caseous mitral annular calcification (CMAC). The color flow Doppler detected a mild mitral regurgitation with a mean pressure gradient of 3.0 mmHg. The subsequent cardiac magnetic resonance revealed a calcified caseous formation of the mitral valve annulus adjacent to the posterior mitral valve leaflet, that was hypointense in both T1- and T2-weighted sequences without early or late contrast enhancement, confirming the suspected diagnosis of CMAC. 
CMAC is a rare variant of the mitral annular calcification, a chronic degenerative process of the fibrous mitral annulus that occurs at advanced age (1-3). Although secondary consequences such as mitral valve regurgitation or stenosis caused by CMAC have been reported, a conservative approach is generally recommended due to the general benign prognosis (4-6). However, this case demonstrates the potentially life-threatening complication that may arise from CMAC. Thus, close clinical follow-up with multi-center research focusing on possible consequences of CMAC and a critical evaluation for oral anticoagulation is warranted. 
In the present case, the patient was recommended surgical resection of the tumor, which he declined. Finally, oral anticoagulation with a non-vitamin K agent was initiated to prevent further thromboembolic events.

FIGURES

Figure 1

Transesophageal echocardiography showing a well-defined, smooth-bordered echo-dense mass with central echolucency at the posterior peri-annular region of the mitral valve causing a mild mitral regurgitation. CMAC, caseous mitral annular calcification.

Figure 2

Cardiac magnetic resonance revealing a T1- and T2-weighted hypointense, calcified caseous formation of the mitral valve annulus, without early or late contrast enhancement. CMAC, caseous mitral annular calcification.