Cystic Formation of the Foramen Ovale Mimicking a Right Atrial Myxoma

A 65-year-old woman presented with shortness of breath, stenocardia, and tachycardia. She underwent several steps of examination. Echocardiography showed a suspicious formation in the right atrium extending into the inferior caval vein. The lesion was suspicious for a myxoma, a thrombus, or a malformation. Intraoperatively this formation presented as a cystic formation connected to the right atrial wall in the area of the foramen secundum and filled with blood and five calcified thrombi. We hypothesize that a slit-like opening in the foramen ovale produced a valve-like mechanism bulging parts of the septum secundum and produced this cystic formation.