Sudden death due to acute pulmonary embolism from asymptomatic right atrial myxoma.

A 21-year-old man, in whom abnormal nodules had been detected in bilateral lung fields with no clinical symptoms for two years, was admitted to the hospital with sudden cardiopulmonary arrest. Acute pulmonary embolism with a large embolus was diagnosed, but the patient died soon after admission. When the examination was compared with X-ray taken 4 days earlier by chance, a large tumor was now detected in the right heart and was suspected to be the cause of this complication after his death. Necropsy found a 3.8 x 3.5 x 1.0 cm myxoid tumor arising in the right atrium and a large fragment of this type of tumor was at the pulmonary trunk. Many old myxoma fragments were noted in the bilateral peripheral branch of the pulmonary artery. It was concluded that the abnormal nodules were old pulmonary fragments and the cause of death was pulmonary embolism of a large fragment originated from the atrial myxoma. An asymptomatic right atrial myxoma is extremely rare but nevertheless possible to unexpected death like this case.