The Thoracic Footprint of Hepatocellular Carcinoma: A Mechanism-Based Imaging Narrative Review.

A thoracic finding in a patient with hepatocellular carcinoma (HCC) may represent metastatic disease, vascular extension, treatment-related injury, or a complication of cirrhosis, and each carries different implications for staging and care. The mechanism behind the finding therefore matters as much as the finding itself. We searched the PubMed/MEDLINE database for articles published up to August 2026 and screened the reference lists of retrieved articles for additional relevant publications. The narrative review is organised into four domains: direct oncological involvement, vascular dissemination, treatment-related injury, and cirrhosis-associated mimics. Within each domain, computed tomography (CT) provides most of the chest assessment, while magnetic resonance imaging, echocardiography, and angiography address more specific anatomical or diagnostic questions. We next discuss common patterns of pulmonary metastasis alongside benign nodules common in transplant candidates, and the biological and small-lesion limitations of functional imaging. Thoracic findings gain meaning in the context of hepatic disease, vascular anatomy, and treatment history. Enhancement and alpha-fetoprotein have never been validated as noninvasive rule-out tests for pulmonary metastasis, so the choice between sampling and surveillance rests on multidisciplinary judgement of the costs of uncertainty, procedural feasibility, and evidence strength.