Pericardial mesothelioma presenting as a suspected ST-elevation myocardial infarction.

Primary cardiac and pericardial tumors are rare entities with an autopsy frequency of 0.001-0.03%. Metastases to the heart and pericardium are much more common than primary tumors. Malignant pericardial mesotheliomas account for up to 50% of primary pericardial tumors. We report the case of a 75-year-old woman with hypertension, dyslipidemia and atrial fibrillation who went to the emergency department due to nonspecific thoracic discomfort of over six hours duration associated with syncope. Physical examination revealed a low-amplitude arrhythmic pulse, no heart murmurs and no signs of pulmonary congestion. The ECG revealed atrial fibrillation with ST-segment elevation in V2-V6, I and aVL. The patient was transferred for emergent coronary angiography, which revealed a long stenosis in the mid-distal portion of the left anterior descending artery. The echocardiogram showed a large pericardial effusion with diffuse thickening of the myocardium. Due to worsening hemodynamics, cardiac rupture was suspected and the patient underwent urgent sternotomy and pericardiotomy with drainage of a large quantity of hematic fluid. The surgeons then identified a large, unresectable tumor occupying the distal half of the anterior portion of the heart. This is, to our knowledge, the first case report of primary pericardial mesothelioma presenting with suspected ST-elevation myocardial infarction. In this case, direct observation of the tumor led to biopsy and the final diagnosis. These are highly malignant tumors and when diagnosed are usually already at an advanced stage.