S5475 Metastatic Hepatocellular Carcinoma Without a Detectable Primary: A Case of Adrenal Involvement in the Absence of Liver Lesions

Introduction: Hepatocellular carcinoma (HCC) is the most common primary liver tumor with a high mortality rate, especially when associated with extrahepatic metastasis. Metastatic disease is typically associated with an advanced primary lesion. Adrenal glands are a common site for metastasis, with one study reporting around 8.8% of all metastatic diseases. While most cases occur concurrently with intrahepatic lesions, we present a case of HCC metastatic to the adrenal gland, with no primary lesion in the liver. Case Description/Methods: A 61-year-old man with a history of hypertension, daily alcohol use, and smoking was diagnosed with portal vein thrombosis, cirrhosis, and hepatitis C during evaluation for abdominal pain and fever one year ago. He established care with the Gastroenterology clinic for his cirrhosis, and initial HCC screening revealed an elevated alpha-fetoprotein level (96 ng/mL), but computed tomography (CT) imaging did not show hepatic lesions. Instead, a 6.8 × 8.8 cm right adrenal mass was identified. The patient was seen by Surgical Oncology for evaluation of his adrenal mass. He was asymptomatic at the time, except for fatigue, and denied any abdominal pain, weight changes, tachycardia, palpitations, and headaches. The mass was resected, and histopathology revealed metastatic carcinoma. Immunohistochemical staining was positive for Hep-Par1, Glypican-3, and AE1/AE3, indicating hepatocellular origin. Repeat imaging, including preoperative CT and postoperative magnetic resonance imaging, did not show any liver lesions (LI-RADS 2). Further staging identified a lytic lesion in the right proximal clavicle, and fine-needle aspiration confirmed metastatic HCC. The patient was referred to Oncology and is currently undergoing systemic therapy with durvalumab. Discussion: We report a case of metastatic HCC to the adrenal gland without a detectable primary liver lesion. While mostly associated with an occult primary liver tumor, multiple imaging studies done in our patient showed no focal lesions in the liver, indicating other explanations. Intraadrenal hepatic heterotopia, the presence of a tissue type in a non-physiological site, is one of the possible explanations, with postulations that it may have an increased neoplastic potential due to compromised vascular supply or biliary drainage. Irrespective of the etiology, our case report emphasizes the risk of developing HCC in patients with cirrhosis and highlights the importance of screening in these patients.