Malignant cystic and necrotic liver lesions: a pattern approach to discrimination.

Malignant primary and metastatic lesions of the liver have a myriad of imaging appearances. Discriminating between the various lesions requires an understanding of the underlying pathophysiology and imaging characteristics that lead to their malignant appearances. A pattern approach of recognition by imaging with understanding of why particular lesions behave the way they do on sonography, CT, MRI, and nuclear scintigraphy can be developed. A broad selection of malignant cystic liver lesions will be displayed in a multimodality pictorial style including hepatocellular carcinoma, cholangiocarcinoma, cystic and necrotic hepatic metastases, biliary cystadenoma/cystadenocarcinoma, epitheloid hemangioendothelioma, hepatoblastoma, and cystic sarcomas. Characteristic imaging features, clinical symptoms, and prognosis will be discussed. Emphasis will be placed on consistent features of these malignant lesions that help to discriminate them from other hepatic disorders.