S5784 A Rare Case of Hepatocellular Carcinoma Presenting With Right Atrial Involvement: Clinical Challenges and Multimodal Treatment

Introduction: Hepatocellular carcinoma (HCC) with right atrial (RA) involvement is a rare but aggressive presentation, often associated with poor prognosis. Standardized treatment guidelines for such cases are lacking due to their rarity. Case Description/Methods: We report the case of a 68-year-old man with a history of hepatitis C-related cirrhosis who was incidentally found to have a right atrial mass during a preoperative evaluation. Imaging and histopathological studies confirmed the diagnosis of metastatic HCC. The patient underwent partial surgical resection of the mass, followed by adjuvant immunotherapy with atezolizumab and bevacizumab. Upon disease progression, he received targeted radiotherapy and was subsequently started on oral lenvatinib. Follow-up imaging showed marked regression of the cardiac mass and no evidence of intrahepatic recurrence. Discussion: This case highlights the value of a multidisciplinary, multimodal treatment approach, including surgery, immunotherapy, radiotherapy, and targeted therapy, for managing advanced HCC with cardiac involvement. It also underscores the need for heightened clinical suspicion and individualized therapeutic strategies in cases with atypical presentations.