Solitary Brain Metastasis From Hepatocellular Carcinoma Masquerading as Acute Ischaemic Stroke: Radiological Diagnosis and Clinical Implications.

Background: Brain metastases from hepatocellular carcinoma (HCC) are rare, with a reported incidence of approximately 0.2%-2.2% of cases. Although uncommon, they may present with acute focal neurological deficits that closely mimic acute cerebrovascular events, posing significant diagnostic challenges in emergency settings where stroke pathways are routinely prioritised. Failure to recognise an underlying structural lesion in this context may lead to inappropriate management and delayed definitive treatment. Case Presentation: A 66-year-old man with chronic hepatitis B infection and biopsy-confirmed HCC (Barcelona Clinic Liver Cancer Stage B; serum alpha-fetoprotein 1000 ng/mL) presented with sudden-onset right-sided weakness, expressive aphasia and facial deviation approximately 4 weeks after initial HCC diagnosis. Noncontrast computed tomography (CT) of the brain demonstrated a hypodense intra-axial lesion in the left frontal lobe with surrounding vasogenic oedema. Because the atypical CT appearance and subsequent heterogeneous contrast enhancement raised suspicion for a neoplastic aetiology, magnetic resonance imaging (MRI) was performed; this revealed a solitary left frontal mass with avid enhancement and facilitated diffusion on diffusion-weighted imaging, which definitively ruled out acute ischaemic stroke. Gradient echo sequences also demonstrated blooming artefact consistent with intralesional haemorrhage. In the context of known HCC, the imaging findings were consistent with a solitary haemorrhagic brain metastasis presenting as a stroke mimic. The patient was discussed at a multidisciplinary tumour board and subsequently transitioned to palliative care owing to advanced systemic disease and poor functional status. Conclusion: Solitary brain metastasis from HCC should be considered in the differential diagnosis of patients presenting with acute focal neurological deficits, particularly when initial CT findings are atypical for ischaemic infarction or when a known primary malignancy is present. Early contrast-enhanced MRI, including diffusion-weighted sequences, is essential for accurate differentiation of stroke mimics and for guiding timely, appropriate clinical management.