Unexpected Left Atrial Tumor Resected During Multidisciplinary Surgery for Renal Cell Carcinoma With Intracardiac Extension

BACKGROUND: Renal cell carcinoma (RCC) with extension into the right atrium is a complex condition that requires a multidisciplinary team approach to resection. CASE SUMMARY: A 79-year-old woman was referred after an ultrasound revealed a renal mass with an inferior vena cava lesion and extension into the right atrium. Resection was planned with the cardiac, urology, and vascular surgery teams. During intraoperative transesophageal imaging, an additional mass was noted in the left atrium. Complete resection was completed. Postoperative pathology revealed the renal, inferior vena cava, and right atrial lesions as RCC with thrombus. The left atrial lesion was identified as a myxoma. DISCUSSION: RCC with extension into the right atrium accounts for fewer than 1% of RCC cases. Surgical resection remains the only potentially curative treatment. A simultaneous intraoperative discovery of a myxoma with concomitant resection is exceedingly rare. TAKE-HOME MESSAGE: This case highlights the importance of a multidisciplinary approach to complex oncologic resection and the importance of intraoperative imaging during surgical resection.