A right atrial mass and colonic cancer in a patient with Lynch syndrome

When we first assessed the patient, a transthoracic echocardiogram showed a mass extending from the inferior vena cava into the right atrium causing obstruction of the tricuspid valve (appendix); contrast-enhancement showed some opacification of the mass (appendix). After assessment and discussion with the patient—considering firstly his generally good physical state, secondly the response of the disease to immune-checkpoint inhibitors, and thirdly, the obstruction of the tricuspid valve—we excised the right atrial mass during beating-heart surgery with partial cardiopulmonary bypass (appendix). Gross macroscopic evaluation of the excised mass showed a small amount of thrombus with mostly tissue consistent with a metastatic process (appendix); histopathological analysis of a sample of the lesion confirmed mucinous adenocarcinoma.