Introduction: Primary cardiac tumors are very rare causes of intracavitary masses, about 5% in all cardiac tumors. Most of them are benign tumors, and 50% are represented by atrial myxomas. They are usually deve-loped in the left atrium, with a pedicle attached to the interatrial septum. The right atrium is an unusual lo-cation and nonspecific signs and symptoms may lead to misdiagnosis. Cardiac myxomas can mimic a wide spectrum of pathologies, with clinical manifestations varying from signs and symptoms determinated by intracardiac obstruction, embolic events or constitutional symptoms. Ascites represents one of the rarest forms of clinical presentation in a patient with a cardiac tumor.

Methods: We present the case of a 58 year old fema-le patient with a 4 years history of chronic obstructive pulmonary disease, on bronchodilator treatment and long-term oxygen therapy. She accused two months duration of abdominal distension, for which she was evaluated in the gastroenterology department, where ascites was documented without being established a specific cause, with further recommendations of diu-retic treatment. The symptoms were refractory to the treatment, so the patient was referred for cardiac eva-luation, with the suspicion of decompensated cor pul-monale. At presentation, the patient was afebrile, with rhythmic cardiac sounds, having a heart rate of 100/minute and a blood pressure of 125/90 mmHg. Jugu-lar venous distension and bilateral pedal edema were present.

Results: The electrocardiogram showed sinus tachycar-dia and low QRS voltage. Transthoracic echocardiogra-phy revealed a lobulated giant mass in the right atrium, which occupied almost the entire cavity, with prolapse towards the right ventricle during diastole. Because the transthoracic echocardiographic views were difficult to obtain and in order to evaluate the origin of the tu-mor, thoracic computed tomography was performed. The examination confirmed the presence of the right atrial mass, with no other intrathoracic tumors. Sub-sequently, transesophageal ecocardiography revealed an narrow-based, flat attachment of the myxoma to the free wall of the right atrium. The patient was re-ferred to the cardiovascular surgery department and she underwent surgical excision of the tumor. The ma-croscopic evaluation of the excised specimen described a yellowish-brown lobulated friable mass, measuring 70/30/35 mm. The histopathological examination reve-aled round to stellate cells in a myxoid stroma, specific for cardiac myxoma. Postoperative evolution required prolonged mechanical ventilation and positive inotro-pic support, but it was slowly favourable and the patient was discharged in good condition.

Conclusions: T his clinical case is particular conside-ring the impressive dimensions of the myxoma, the uncommon localization in the right atrium, and the rare clinical presentation as ascites. We also emphasize that right heart tumors should be considered in diffe-rential diagnosis of unexplained ascites.