An incidental focal liver lesion (IFLL) is defined as a hepatic lesion identified in a patient imaged for an unrelated reason. They are frequently encountered in daily practice, sometimes leading to unnecessary, invasive and potentially harmful follow-up investigations. The clinical presentation and the imaging aspects play an important role in deciding if, and what further evaluation, is needed. In low-risk patients (i.e., without a history of malignant or chronic liver disease or related symptoms), especially in those younger than 40 years old, more than 95% of IFLLs are likely benign. Shear Wave liver Elastography (SWE) of the surrounding liver parenchyma should be considered to exclude liver cirrhosis and for further risk stratification. If an IFLL in a low-risk patient has a typical appearance on B-mode ultrasound of a benign lesion (e.g., simple cyst, calcification, focal fatty change, typical hemangioma), no further imaging is needed. Contrast-Enhanced Ultrasound (CEUS) should be considered as the first-line contrast imaging modality to differentiate benign from malignant IFLLs, since it has a similar accuracy to contrast-enhanced (CE)-MRI. On CEUS, hypoenhancement of a lesion in the late vascular phase is characteristic for malignancy. CE-CT should be avoided for characterizing probable benign FLL and reserved for staging once a lesion is proven malignant. In high-risk patients (i.e., with chronic liver disease or an oncological history), each IFLL should initially be considered as potentially malignant, and every effort should be made to confirm or exclude malignancy. US-guided biopsy should be considered in those with unresectable malignant lesions, particularly if the diagnosis remains unclear, or when a specific tissue diagnosis is needed.
偶发性肝脏局灶性病变（IFLL）指因其他原因接受影像学检查时偶然发现的肝脏病变。这类病变在日常临床实践中十分常见，有时会导致不必要、有创且可能有害的后续检查。临床表现和影像学特征对于决定是否需要进一步评估以及采取何种评估方式至关重要。在低风险患者（即无恶性肿瘤或慢性肝病史及相关症状者）中，特别是40岁以下人群，超过95%的IFLL可能为良性。应考虑对周围肝实质进行剪切波弹性成像（SWE），以排除肝硬化并进行进一步风险分层。若低风险患者的IFLL在B超下呈现典型良性病变特征（如单纯性囊肿、钙化灶、局灶性脂肪变、典型血管瘤），则无需进一步影像学检查。对比增强超声（CEUS）应作为鉴别IFLL良恶性的首选增强影像学方法，因其诊断准确性与增强磁共振（CE-MRI）相当。在CEUS检查中，病变在晚期血管期呈低增强是恶性肿瘤的特征性表现。应避免使用增强CT（CE-CT）评估可能良性的FLL，该检查应仅用于病变确诊恶性后的分期评估。对于高风险患者（即患有慢性肝病或有肿瘤病史者），每个IFLL最初都应被视为潜在恶性病变，并应尽一切努力确认或排除恶性可能。对于不可切除的恶性病变患者，特别是诊断仍不明确或需要明确组织病理诊断时，应考虑超声引导下活检。
WFUMB Review Paper. Incidental Findings in Otherwise Healthy Subjects, How to Manage: Liver
肿瘤(癌症)患者之家