RESUMEN
BACKGROUND: Renal cell carcinoma (RCC) is an aggressive tumor, with an incidental discovery in most patients. Classic presentation is rare, and it has a high frequency of local and distant metastasis at the time of detection. CASE SUMMARY: We present a rare case of a 58-year-old man with a ball-shaped thrombus in the right atrium at the time of first incidental identification of RCC in the emergency department. Cardiac metastasis, especially thrombus in the right atrium, is rare. It could either be a bland thrombus or a tumor thrombus, and physicians should consider this potentially fatal complication of RCC early at the time of initial presentation. CONCLUSION: Ball-shaped lesions in the right atrium are rare, and bland thrombus should be differentiated from tumor thrombus secondary to intracardiac metastasis.