非肝細胞性悪性腫瘍

Imaging of non-hepatocellular malignant liver tumors

肝悪性腫瘍の画像診断では肝細胞癌が中心となるが，日常診療では非肝細胞性悪性腫瘍に遭遇する機会も少なくない。これらは転移性腫瘍を除けば頻度こそ低いものの，特徴的な画像所見や重要な鑑別点を有する。本稿では代表的な非肝細胞性悪性腫瘍を取り上げ，実臨床で疾患を疑うための画像所見，鑑別診断，およびピットフォールを概説する。

Although hepatocellular carcinoma is the most common primary liver malignancy, radiologists frequently encounter non-hepatocellular malignant tumors in daily practice. This article reviews the imaging features and differential diagnoses of representative non-hepatocellular malignant liver tumors, including intrahepatic cholangiocarcinoma（iCCA）, metastatic liver cancer, primary hepatic lymphoma, hepatic angiosarcoma, and epithelioid hemangioendothelioma. We emphasize the recent updates in iCCA classification（small duct vs. large duct types）and highlight key imaging characteristics on CT and MRI, such as contrast enhancement patterns, diffusion restriction, and morphological changes like capsular retraction. Understanding these distinct imaging findings is crucial for accurate diagnosis and optimal patient management.