Primary malignant pericardial mesothelioma with increased serum mesothelin diagnosed by surgical pericardial resection: A case report.

A 37-year-old female smoker without a history of exposure to asbestos was referred to our hospital with persistent pericardial effusion. Chest computed tomography imaging examination revealed an irregular thickened pericardium with large amounts of pericardial effusion and a small pleural effusion. Fluorodeoxyglucose (FDG) positron emission tomography imaging demonstrated intrapericardial FDG accumulation. Blood tests revealed an increase in serum mesothelin levels. Examination of a surgically resected specimen revealed a grayish-white thickening of the pericardium, with a straw-colored mucinous pericardial effusion. Histopathological examination confirmed the diagnosis of epithelioid malignant mesothelioma. Although the patient's condition temporarily improved, with decreased levels of serum mesothelin during chemotherapy with carboplatin and pemetrexed, she succumbed to cardiac tamponade 18 months after the initial onset of the symptoms. Primary malignant pericardial mesothelioma (PMPM) is an extremely rare and refractory disorder. Thus, an early definitive diagnosis and timely treatment are crucial for the management of PMPM.