Right Atrial Primary Cardiac Lymphoma Presenting With Stroke
An immunocompetent 79-year-old man presented with acute dysarthria and hemiparesis on the left side. The cranial CT revealed the typical findings of a middle cerebral artery territory infarction of embolic origin, likely from previously unknown nonvalvular atrial fibrillation. The results of the duplex ultrasound of the carotid arteries were normal. Transesophageal echocardiography, however, showed a right atrial tumor, which suggested either thrombus or myxoma (Figure 1A, Movie I). No evidence of a thrombus or spontaneous echo contrast was observed in the left atrium; the mean left atrial appendage peak emptying velocity was 0.35 m/s. Moreover, few microbubbles appeared in the left atrium, although only after >3 heart cycles (Figure 1B, Movie II). In combination with the findings from contrast transcranial Doppler ultrasound, which showed 3 bubbles within 20 seconds, some evidence of right-to-left shunting was noted, although the formal echocardiographic criteria of a patent foramen ovale were not fulfilled. The thoracic CT showed a right atrial tumor extending into the superior vena cava (VCS), as well as pericardial and right-sided pleural effusions (Figure 2). After surgical removal of the tumor the histological examination surprisingly revealed a primary cardiac non-Hodgkin lymphoma (PCL). The immunohistochemical classification showed a diffuse large B cell lymphoma with high immunoglobulin M expression. An extensive diagnostic work-up yielded no evidence of an extracardial lymphoma manifestation. The patient refused all therapy and died 6 weeks later at home.
In our patient, the PCL, which is per se a rare entity, presents the unique origin of stroke. Two different pathophysiological mechanisms are conceivable: The dilatation of the right atrium may have caused atrial fibrillation predisposing to cardioembolism. Alternatively, although rather unlikely, increased thrombogenicity resulting from turbulent flow and the large surface of the tumor in the right atrium may have facilitated a paradoxical embolism either through a small patent foramen ovale or a pulmonary shunt.
The online-only Data Supplement, which contains Movies I and II, is available with this article at http://www.circulationaha.org.