Magnetic resonance imaging of pericardial malignant mesothelioma

Epidemiology of mesothelioma of the pericardium and tunica vaginalis testis

PURPOSE

Malignant mesothelioma most commonly arises in the pleura and peritoneum but also occurs rarely at other anatomical sites with mesothelial tissue, namely, the pericardium and tunica vaginalis testis (TVT). This review provides a better understanding of the epidemiology of mesothelioma of these extrapleural sites.

METHODS

We conducted a systematic review of the epidemiologic and clinical literature on pericardial mesothelioma and mesothelioma of the TVT. We also analyzed U.S. Surveillance, Epidemiology, and End Results cancer registry data to describe incidence patterns of these malignancies.

RESULTS

An etiologic role of asbestos exposure has been hypothesized for pericardial and TVT mesotheliomas, but no analytical case-control epidemiologic studies exist to test this relationship. A substantial proportion of cases with these malignancies report no known asbestos exposure. In large occupational cohorts with heavy asbestos exposures, no cases of pericardial or TVT mesothelioma have been reported. Trends in the incidence of these malignancies do not match those of pleural mesothelioma, which correspond to historical trends of commercial asbestos use. A male preponderance of pericardial mesothelioma is not evident.

CONCLUSIONS

In the absence of analytic epidemiologic studies, the etiologic role of environmental risk factors for mesothelioma of the pericardium and TVT remains elusive.

Primary Pericardial Mesothelioma: Report of a Patient and Literature Review

Primary mesothelioma of the pericardium is a rare tumor and carries a dismal prognosis. This case report presents a 38-year-old man who suffered from recurrent pericardial fluid. Initial symptoms were unspecific, with dry cough and progressing fatigue. Pericardiocentesis was performed, but analyses for malignant cells and tuberculosis were negative. After recurrence a pericardiectomy was planned. At operation, partial resection of tumor tissue surrounding the heart was performed. Histopathologic examination including immunohistochemical staining for calretinin showed a biphasic mesothelioma. During the postoperative period the patient's condition ameliorated, but symptoms recurred and the patient died 3 months after diagnosis and 15 months after the first symptoms. At autopsy, the pericardium was transformed by the tumor that also expanded into the mediastinum and had set metastases to the liver. A review of 29 cases presented in the recent literature indicates a higher incidence of malignant pericardial mesothelioma among men than women. Median age was 46 (range, 19-76) years. In pleural mesotheliomas, exposure to asbestos is a known risk factor. However, in primary pericardial mesotheliomas the evidence for asbestos as an etiologic factor seems to be less convincing (3 exposed among 14 cases). Symptoms are often unspecific and cytologic examination of pericardial fluid is seldom conclusive (malignant cells demonstrated in 4/17 cases). Partial resection of the tumor can give a period of symptom reduction. Only a few patients have been treated with chemotherapy. Median survival of patients with pericardial mesotheliomas is approximately 6 months.

Role of magnetic resonance imaging for evaluation of tumors in the cardiac region

The aim of this study was to review the role of MRI in the assessment of heart neoplasm, 25 cases with heart neoplasm (10 myxoma, 6 rhabdomyoma, 5 angiosarcoma, 2 mesothelioma, 1 lymphoma, and 1 fibroma) were examined with MRI and echocardiography. Multislice T1- and T2-weighted spin-echo images and static gradient-echo images were taken in appropriate directions with electrocardiogram gating. Gadolinium enhancement was performed in 21 cases. Transthoracic echocardiography was performed in all cases. Except for the 5 patients with rhabdomyoma, the pathological diagnosis was obtained. MRI proved to be useful for tissue characterization of myxoma, angiosarcoma, mesothelioma, and fibroma in cases with tuberous sclerosis. MRI also proved to be useful for detection of the tumor, depiction of contour, relation with other cardiac structures, in cases with myxoma, angiosarcoma, mesothelioma, lymphoma, and fibroma. In the differential diagnosis, MRI provided important information in cases with myxoma, rhabdomyoma, angiosarcoma, and fibroma. In cases with tumors expanding into the mediastinum, such as mesothelioma and fibroma in this report, MRI was useful in determining the location and border. In cases with tumors adjacent to pericardium, MRI was useful in detecting pericardial invasion. Gadolinium enhancement added useful information in cases with myxoma, rhabdomyoma, angiosarcoma, and mesothelioma. The role of MRI with and without Gd enhancement differs somewhat in individual types of heart neoplasm, and adaptation must be considered in each kind of neoplasm. On the other hand, MRI is an essential examination in all cases with a cardiac mass, which has not been diagnosed, since it may provide useful information for the differential diagnosis.