Which lesion is a key differential diagnosis for a vascular hepatic lesion that can mimic a hemangioma on imaging?

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When a vascular-looking lesion in the liver mimics a hemangioma on imaging, the key differential to keep in mind is a metastatic lesion. Metastases can be highly vascular and, depending on the primary tumor and the imaging window, may show enhancement patterns that resemble the classic peripheral nodular enhancement with gradual fill-in seen in hemangiomas. This overlap is why metastasis must be considered, especially if there are multiple lesions, atypical margins, or a history of cancer, or if the lesion behaves atypically on follow-up or with diffusion imaging.

In contrast, focal nodular hyperplasia and hepatic adenoma each have more distinctive imaging or clinical features, such as a central scar in FNH or fat and hemorrhage tendencies in adenoma, which help distinguish them from a benign hemangioma. Hepatocellular carcinoma typically shows arterial enhancement with washout in later phases and often occurs in the setting of cirrhosis or other risk factors, making it less likely to masquerade as a benign hemangioma. Thus, metastasis stands out as the important differential when a vascular hepatic lesion resembles a hemangioma on imaging.