Approximately 45% of the patients with RCC present localized tumors, 25% of patients present locally advanced disease, and approximately 30% of patients may have metastases at the time of diagnosis . Cardiac metastases of RCC occur through two mechanisms. The first is a lymphatic pathway through the lymphatic vessels of the thorax collecting the drainage from the posterior wall of the heart. Reports have mentioned that drainage from the left heart wall passes through these lymph vessels and lymphatic flow can be reversed by metastasis to the nodes . The second mechanism involves a venous hematogenous pathway through the renal vein to the right heart. In cases with isolated and delayed progression to the right heart without involvement of the IVC remain the most probable mode of metastasis through venous hematogenous micro dissemination . This mechanism of metastasis is more compatible with the present case because of an isolated lesion and the right heart.
Patients with cardiac metastases present nonspecific symptoms such as palpitations, chest pain, shortness of breath, and syncope. Coronary occlusion or compression from tumor masses can lead to myocardial infarction, eventual heart failure, and even death . A high index of suspicion is required to make a timely diagnosis of cardiac metastases because of the nonspecific clinical symptoms. Although various diagnostic imaging modalities have been used in prior reports, cardiac MRI is recommended as a reliable tool for evaluating the cardiac masses given its excellent contrast resolution and tissue characterization, which can exclude lipomas, fibromas, and hemangiomas as well as thrombus or lipomatous hypertrophy . Also, cardiac CT provides high-quality images with superior spatial resolution for evaluation of relationship between the tumor and coronary arteries for surgical planning for the mass resection .
Unlike most other neoplasms, metastatic RCC is relatively resistant to conventional chemotherapy. Moreover, angiogenesis inhibitors, cytokine-based therapy including interferon, were the mainstay of treatment for advanced RCC. The development of drugs known as receptor tyrosine kinase inhibitors including sorafenib and sunitinib has created a paradigm shift in the treatment of RCC. Some reports have described cases of sudden death due to malignant cardiac metastases . However, there is no consensus regarding surgical treatment for such disease. While the patients with isolated cardiac metastasis of RCC generally have obstructive symptoms; surgical resection may provide effective and favorable outcomes by preventing tumor embolism . In this case, the free wall of the tumor adhesion site was thinned and the muscular layer remained. Moreover, RV branch was running on the center of the tumor lesion. Therefore, the transmural wall resection was not performed to avoid postoperative RV dysfunction by over-invasive surgery. In addition, cryoablation was managed against the RV wall to prevent tumor cell remnants. A pen-type freeze coagulation device frequently used in maze procedure for atrial fibrillation was adopted. The procedure was adopted after referring to some multidisciplinary treatment combining hepatectomy, microwave coagulo-necrotic therapy (MCN), and postoperative chemotherapy. It has been reported that this treatment may provide long-term survival for patients with unresectable metastatic hepatocellular carcinoma [9, 10]. However, there is no report on the effectiveness of MCN for metastasis of renal cell carcinoma. Surgical resection acts as palliation therapy of malignant cardiac metastasis; thus, multidisciplinary therapy as a combination of surgical treatment and targeted molecular therapy with cooperation of multiple experts is essential. For carefully selected patients, surgical resection of cardiac metastases to provide symptom palliation, improved quality of life, and prolonged survival may be acceptable.