Differential diagnosis of intracavitary tumors obstructing the right ventricular outflow tract.

Three cases of right ventricular outflow tract obstruction caused by 3 distinct tumors-myxoma, sarcoma, and presumed metastatic tumor-diagnosed by transthoracic and transesophageal echocardiography are presented. The differences among these 3 types of tumors with similar clinical and echocardiographic findings are highlighted, and a review of the pertinent literature is discussed. By applying the approximate frequencies of cardiac tumors categorized by type and site, statistically, an intracavitary right ventricular outflow tract tumor is 70 to 140 times more likely to be malignant than benign; furthermore, if it is a primary cardiac tumor, it is approximately 2 times more likely to be a sarcoma than a myxoma.