Witnessing a rare event - thrombus seeking its route in the right atrium: 'thrombus-in-transit'.

Pulmonary embolus and right atrial thrombus trapped in a patent foramen ovale is an unusual, rare condition. We report a case of impending paradoxical embolism with pulmonary embolism, in which a thrombus entrapped in a patent foramen ovale was detected. To our knowledge, this is the first case in the literature in which 'thrombus-in-transit' was detected in the right atrium both before and after entrapment in a patent foramen ovale.