S5450 When Liver Cancer Strikes the Kidney: A Case of Uncommon Metastasis

Introduction: Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide. Common metastatic sites include the lungs, lymph nodes, bones, and adrenal glands. This case report describes a rare instance of HCC metastasizing to the left kidney, emphasizing the need for increased surveillance, routine imaging, and interdisciplinary care to improve outcomes. Case Description/Methods: A 72-year-old woman with a past medical history of cured hepatitis C, liver cirrhosis and chronic smoking was referred to oncology after a liver lesion meeting criteria for HCC was identified during routine surveillance. Initial investigations showed an elevated alpha-fetoprotein (AFP) of 62.6 ng/mL. A magnetic resonance imaging (MRI) of the abdomen revealed a 5.1 cm hepatic mass and a 2.3 cm benign adrenal adenoma. A computed tomography (CT) chest detected a 4 mm left upper lobe nodule. In September 2022, she underwent open resection of hepatic segments V, VI, and II. Pathology confirmed HCC in segments V and VI, while segment II revealed a bile duct adenoma. She was followed with surveillance scans every 3 months. An April 2023 CT chest scan showed a growing 1.1 cm solid left upper lobe nodule with spiculated margins. She underwent a left upper lobe wedge resection in June 2023, with pathology identifying a second primary squamous cell malignancy. Follow up chest CT was negative for recurrent lung disease. An MRI in February 2024 revealed multiple liver lesions, a left renal vein thrombus and an associated renal infarct. By April 2024, a new 1.8 cm HCC lesion appeared in segment V, with renal thrombus progression. The patient was started on apixaban for therapeutic anticoagulation. She underwent microwave ablation of segment V in June 2024. A renal biopsy in November 2024 confirmed metastatic HCC. Systemic immune checkpoint inhibitors (tremelimumab + durvalumab) were initiated. No targetable mutations were found via NGS of the biopsied sample. A month later, an adrenal nodule biopsy also confirmed metastatic HCC. Immunotherapy was continued, as treatment failure was inconclusive. Discussion: Renal metastases from HCC are rare, typically unilateral and asymptomatic, with only 11 cases reported. Among 6 with documented outcomes, 3 died within 3 months, while 3 had improved survival post-nephrectomy or embolization with sorafenib. In our case, immune checkpoint inhibitors were used instead of sorafenib due to superior survival benefits. Evidence from additional reports are needed to guide optimal treatment for renal metastasis from HCC.