IntroductionPrimary malignant pericardial mesothelioma is a very rare pericardial tumor of unknown etiology.Case presentationA 61-year-old Caucasian woman was admitted to our hospital complaining of exertional dyspnea due to a large pericardial effusion. Intrapericardial fluid volume declined after repeated pericardiocentesis, but the patient progressively developed a hemodynamically relevant pericardial constriction. Pericardiectomy revealed a pericardial mesothelioma. Subsequently, four cycles of chemotherapy (dosage according to recently published trials) were administered. The patient remained asymptomatic, and there was no recurrence of the tumor after three years.ConclusionPericardial mesothelioma should be considered and managed appropriately in non-responders to pericardiocentesis, and in patients who develop constrictive pericarditis late in their clinical course.