Ping-Pong Ball, Tumor or Thrombus in the Right Atrium? A Case Report.

Tumors and thrombi are the most common cardiac masses of the right atrium. The use of noninvasive imaging to differentiate between the two can be deceiving, and the clinical judgment of a cardiologist and the emergency of the situation should be partnered to decide on the next step of the management. We present the case of a 29-year-old lady who was receiving neoadjuvant treatment for her rhabdomyosarcoma and was incidentally found to have a very large, very mobile right atrial mass that was protruding in the right ventricle with each cardiac cycle along with findings of a small segmental right lower lobe pulmonary embolism. Along with noninvasive imaging, frozen section analysis procured the wrong diagnosis, and the mass was ultimately found to be a right atrial thrombus on definite pathology review. Exact management of right atrial masses continues to be not well delineated, and when in doubt, final diagnosis might need to be "a posteriori" and based on the treatment response.