A patient with an unusual cyst of the inter-atrial septum and atrial sepal defect.

Hepatic and renal cysts are relatively common among healthy people, but there are few published reports of primary cysts of the atrial septum. Here, we report a case of an unusual cyst of the atrial septum accompanied by atrial septal defect (ASD) in a 42-year-old woman. Microscopic examination showed the deposition of calcium salts within the tissue mass and an organized thrombus surrounded by a fibrous capsule. The case was discussed with reference to the relevant published literature and compared to other documented types of atrial septal cysts. The final diagnostic conclusion was a primary atrial septal cyst.