A Dramatic Response to Immune Checkpoint Inhibitor in a Patient with a Bulky Intra Cardiac Metastasis in Renal Cell Carcinoma: A Case Report

Background: New therapies, including oral multitargeted Tyrosine Kinase Inhibitors (TKIs) and immune checkpoint inhibitors (IO), have significantly increased survival in the majority of patients with metastatic Renal Cell Carcinoma (mRCC). Common sites of RCC metastases are lymph nodes, lung, liver, and bone but some unexpected clinical presentations sometimes occurred as cardiac metastasis without validated treatment. We described a case report of a patient presenting cardiac metastasis treated with IO who showed a dramatic durable response, which was prolonged despite stopping the drug. Case Presentation: A 51-year-old man was treated by radical nephrectomy and hepatic segmentectomy in 2008 for a locally advanced Clear Cell Renal Cell (CCRC) carcinoma. Between 2009 and 2015, successive localized progressions were treated by several focal treatments, including surgery and interventional radiology, and intermittent TKIs including sunitinib and axitinib. Because of systemic dissemination with lung metastasis, nephrectomy site recurrence and a bulky intracardiac metastasis, the patient received anti-PD1 nivolumab with a dramatic response. In 2017, a new disease progression at the site of the nephrectomy recurrence associated with colonic invasion was treated with a right colectomy and resection of local nephrectomy recurrence. Nivolumab was planned to restart again. But, subsequent to the surgery, acute promyelocytic leukemia was diagnosed. Specific treatment was started and nivolumab was not reintroduced. In March 2018, complete remission of leukemia with the negative minimal residual disease was achieved. In March 2019, the dramatic efficacy on the intracardiac metastasis and nephrectomy lodge was still maintained. Conclusion: Cardiac metastases from RCC are considered to be rare and no standard treatment is validated. We report the first case of an IO blocker response on cardiac metastases in the context of metastatic RCC. In addition, immunotherapy efficacy was maintained over time, even after treatment discontinuation and regardless of metastasis localization.