RESUMEN
A 76-year-old woman presented because of bilateral lower-extremity edema and dyspnea. Transthoracic echocardiography revealed a mobile mass in the right atrium. A right atrial mass associated with heart failure was diagnosed. Surgery was performed. Intraoperative transesophageal echocardiography showed that the mass was contiguous with the inferior vena cava. However, the primary lesion was unclear. Therefore, only the intracardiac mass was resected. The margins of the residual tumor were marked with clips. Computed tomography performed immediately after surgery revealed a clip in structures contiguous with the region from a uterine myoma to the inferior vena cava. Intravenous leiomyomatosis was diagnosed on histopathological examination of the resected specimens. Computed tomography 6 months after surgery showed that the clip had moved from the inferior vena cava to a vein contiguous with the uterus. The tumor regressed slightly. Close follow-up is required.