A chiari network mimicking a cystic structure.

The Chiari network is a net-like mobile structure, occasionally encountered near the entrance of the inferior vena cava in the right atrium. Due to its fenestration, the Chiari network does not cause flow obstruction of the blood. The Chiari network is usually an incidental finding with no further clinical consequences. We report an unusual presentation of a Chiari network, mimicking a right atrial oscillating cystic mass attached to the interatrial septum by a thin stalk.