偶発的に発見された右房血液囊腫

Incidentally Detected Right Atrial Blood Cyst

心内血液囊腫は新生児期に房室弁近傍で高頻度に認められるが，多くは成長とともに消退し，生後6ヵ月以降に認められることはきわめてまれであるとされてきた1）．しかしながら，近年では画像診断技術の進歩に伴い，成人の報告例が散見される．われわれは，心房中隔から発生した成人の右房血液囊腫の1手術例を経験したので報告する．

A 48-year-old man underwent computed tomography for the examination of lower back pain, which incidentally detected a cardiac tumor in the right atrium. On echocardiography, the tumor was identified as a 30 mm round mass with a thin wall and iso- and hyper-echogenic contents that originated from the atrial septum. The tumor was successfully removed under cardiopulmonary bypass, and the patient was discharged in good health. The cyst was filled with old blood, and focal calcification was observed. Pathological examination revealed that the cystic wall was composed of thin-layered fibrous tissue lined with endothelial cells. Regarding a treatment, it is reported that early surgical removal is preferable to avoid embolic complications, however it is controversial. Furthermore, it needs to discuss about the difference between fetal/neonatal and adult cases.