Rare Malignant Liver Tumors: Current Insights and Imaging Challenges

Rare malignant liver tumors (RMLTs) comprise a diverse group of neoplasms with distinct imaging features and significant diagnostic challenges due to their low prevalence and overlap with more common hepatic lesions. This review highlights the main radiologic characteristics of selected rare malignant liver tumors—including fibrolamellar hepatocellular carcinoma, hepatic lymphoma, hepatocellular carcinoma in non-cirrhotic liver, mucinous cystic neoplasm, intraductal papillary neoplasm of the bile duct, epithelioid hemangioendothelioma, angiosarcoma, malignant hepatic adenoma, neuroendocrine tumor, hepatocholangiocarcinoma, hepatoblastoma, undifferentiated embryonal sarcoma, and infantile hepatic hemangioendothelioma—focusing on their presentation in computed tomography and magnetic resonance imaging. Recognizing specific imaging findings, such as arterial hyperenhancement, biliary communication, target and lollipop signs, and tumor morphology, can help narrow differential diagnoses and guide appropriate clinical management. Despite advancements in imaging, histopathologic confirmation is often required due to nonspecific features. Improved radiologic awareness of these rare entities is essential to facilitate early diagnosis and individualized treatment planning.