Right mesothelial pericardial cyst determining intractable atrial arrhythmias.

Pericardial cysts are intrathoracic lesions usually considered to be congenital and less frequently to be acquired. They are normally found incidentally upon chest radiography, computed tomography (CT)-scan or echocardiography. They are usually asymptomatic and have a benign behavior although sometimes they can cause clinical symptoms and diagnosis can be uncertain. We present, herein, the case of a 51-year-old male with a history of atrial arrhythmia resistant to transcatheter ablation therapies with an accidental finding of a pericardial cyst adherent to the lateral wall of the right atrium at the emerging superior vena cava. The patient was studied with transesophageal echocardiography, CT-scan and cardiovascular magnetic resonance with the evidence of dimensional increasing of the cyst at seriate controls. Considering this, in the absence of a definitive diagnosis and suspecting a link between the mass and the arrhythmia, the cyst was surgically removed through median sternotomy, off-pump on a beating heart. Postoperative course was unremarkable. Histopathologic examination confirmed it was a mesothelial pericardial cyst. At 12 months of follow-up the patient is doing well and he is in sinus rhythm. In conclusion, we believe that, although the majority of pericardial cysts need only radiological and clinical follow-up, surgical resection should be performed when the patient is symptomatic and when diagnosis is uncertain.