Ectopic Hepatocellular Carcinoma Metastasizing to the Brain with Initial Presentation as Tumor Stroke Syndrome: A Case Report

Abstract Ectopic hepatocellular carcinoma (HCC) with brain metastasis is exceptionally rare and carries a poor prognosis. We report a case initially presenting with tumor stroke syndrome manifesting as sudden unconsciousness and unresponsiveness. Emergency intracranial hematoma evacuation was performed, and histopathology confirmed brain metastasis of hepatocellular carcinoma. Subsequent PET/CT localized the primary ectopic HCC to the left lung lower lobe. This case underscores the critical role of radiological evaluation (CT/MRI for diagnosis/prognosis; PET/CT for primary lesion identification) in such scenarios. For patients with tumor stroke as the initial symptom, prompt suspicion of hemorrhagic malignant brain metastasis is essential, requiring emergent intervention and pathological confirmation. Notably, markedly elevated alpha-fetoprotein combined with extrahepatic FDG-avid masses on PET/CT strongly suggests ectopic HCC.