Preventing false positive imaging diagnosis of HCC: differentiating HCC from mimickers and practical strategies

Noninvasive imaging-based diagnosis of hepatocellular carcinoma (HCC) in high-risk patients plays a central role in clinical practice. Current major guidelines typically rely on the radiologic hallmark of nonrim arterial phase hyperenhancement followed by nonperipheral washout, criteria designed to achieve both high positive predictive value and sufficient specificity when applied within well-defined target populations. Despite these criteria, false positive diagnoses still occur and can lead to unnecessary or inappropriate treatment, as various benign and non-HCC malignant lesions may exhibit vascular features that overlap with the classic appearance of HCC. Furthermore, treatment decisions are occasionally guided by imaging findings even in patients outside the target population who are being evaluated for possible HCC, in whom vascular patterns are less specific and the risk of false positive diagnosis is inherently higher. Minimizing the risk of false positive diagnosis requires not only adherence to validated imaging criteria but also clinical and contextual integration when findings are uncertain. This includes consideration of ancillary features, tumor markers, and, when appropriate, further evaluation through biopsy, additional imaging, or follow-up. This review outlines a range of HCC mimickers and provides practical strategies to support accurate imaging interpretation and reduce false positive diagnoses in clinical practice.