Cardiac blood cysts are rare benign neoplasms, usually involving the cardiac valves and are remnants of the Chiari network. They are usually detected in the first six months of life and rarely occur in children or adults. We report a 76-year-old male patient who was referred to the Imam Ali Hospital affiliated with Kermanshah University of Medical Sciences, Kermanshah, Iran, in 2018 with dyspnoea. Transthoracic echocardiography revealed a small patent foramen ovale (PFO) and a circumferential mobile cystic mass in the right atrium, with the impression of a tumour or thrombus. The patient underwent open-heart surgery with cardiopulmonary bypass to repair to PFO and remove the intra-atrial lesion. During surgical examination of the right atrial cavity, a blood cyst containing small stone-like structures on the coronary sinus valve of the right atrium was found. The post-operative course was uneventful and no recurrence of tumour was detected during six months of follow-up. To the best of our knowledge, this is the first reported case of a right atrial blood cyst with a few nodule-like stones in an adult with PFO in Iran and the second case in an adult with PFO worldwide.

Cardiac blood cysts are rare benign neoplasms, usually involving the cardiac valves and are remnants of the Chiari network. They are usually detected in the first six months of life and rarely occur in children or adults. We report a 76-year-old male patient who was referred to the Imam Ali Hospit...