Malignant mesothelioma is a rare malignant disease affecting the pleura, less commonly the pericardium and other serous membranes. The most common presenting symptoms are dyspnea, cough, and chest pain. Concerning cardiac involvement, malignant mesothelioma of the pericardium is known to cause constrictive pericarditis and pericardial effusion . Invasion of the tumor into the myocardium causing LV dysfunction has also been described .
We searched medical databases for keywords “mesothelioma left ventricular dysfunction”/scarring”/aneurysm”, “mesothelioma heart failure”, and reviewed available case reports. To our knowledge, a case of malignant mesothelioma causing localized LV dysfunction has not yet been described apart from cases in which malignant mesothelioma invaded the myocardium . Since an invasion of the tumor into the myocardium was not detected in our patient, we attributed formation of a myocardial scar to proximity of malignant mesothelioma with the myocardium. External compression by the tumor mass is one of the possible causes of localized LV dysfunction. Another possible yet unexplored mechanism is a release of the cytokines and other mediators from malignant mesothelioma to the adjacent myocardium.
In general, tumors and other masses can cause LV dysfunction by external compression of the coronary artery [4, 5]. In our patient, this mechanism is unlikely in the absence of correlating changes in the coronary angiography. Mechanical compression of the myocardium is also a possible explanation for signs and symptoms of heart failure as in patients with pectus excavatum . Also, a case of malignant mesothelioma causing heart failure due to mechanical compression of right atrium has been described . However, it is unlikely to cause localized dysfunction of the LV and scar formation.
Malignant mesothelioma is known to be resistant to cytostatic therapy and the immune suppressive microenvironment is likely contributing to this therapy resistance. Therefore, it was studied in an attempt to target the cytokines and their receptors deemed responsible for the progression of the tumor with the biological therapy. Malignant mesothelioma was found to attract cancer-associated fibroblasts and fibrocytes and macrophages with their collagenolytic activity responsible for tissue remodeling . In our patient, these mechanisms may have also influenced the myocardium in close proximity to the tumor causing its fibrosis.
While we cannot omit the possibility that the correlation of localization of mesothelioma and the myocardial scar is coincidental, such a perfect correlation of the site of the tumor and myocardial fibrosis is striking. Apart from that, localized myocarditis is likewise improbable in this case as CMR did not reveal any myocardial edema. Both malignancy and myocarditis could be caused by radiation, however, our patient did not have any history of radiation exposure.