Emergency Surgery for Left Atrial Metastatic Alveolar Rhabdomyosarcoma Manifesting as a Right Atrial Mass

We report the case of a 43-year-old woman with a history of alveolar rhabdomyosarcoma of the forearm, scalp, and paraspinal region who developed acute shortness of breath owing to a tumor arising from the left atrium and extending through the coronary sinus. This was causing partial obstruction across the tricuspid valve as a result of the ball-valve effect. Emergency resection of the atrial mass was performed, and histologic analysis confirmed the presence of metastatic rhabdomyosarcoma. To our knowledge, this is the first reported case of emergency surgical resection of intracardiac metastatic alveolar rhabdomyosarcoma.