肝脏血管周上皮样细胞肿瘤的影像学诊断 与病理对照分析研究

Imaging Diagnosis and Pathological Correlative Analysis of Hepatic Perivascular Epithelioid Cell Tumor

摘要: 目的：探讨肝脏血管周上皮样细胞肿瘤(hepatic perivascular epithelioid cell tumor, hepatic PEComa)的影像学特征、病理特点及鉴别诊断要点，提升对该少见肿瘤的影像学诊断水平。方法：回顾性分析经手术病理及免疫组化证实的hepatic PEComa患者的病历资料，详细描述其CT、MRI的检查方法及影像学表现，并与病理结果进行对照分析，结合相关文献总结其临床、影像及病理特征。结果：患者为51岁女性，无明显临床症状，实验室检查肿瘤标志物及肝炎相关指标均正常。影像学示肝尾状叶单发结节；CT平扫为低密度影，增强扫描动脉期显著不均匀强化，门静脉期及延迟期局部廓清；MRI示病灶呈长T1长T2信号，DWI高信号但ADC值未减低，增强扫描动脉期显著不均匀强化，门静脉期及移行期局部廓清，肝胆特异期呈低信号，病灶无包膜、无明显脂质成分。术后病理及免疫组化确诊为hepatic PEComa，免疫组化示HMB45、Melan-A弥漫阳性，SMA阳性，Desmin阴性等。结论：肝脏血管周上皮样细胞肿瘤是肝脏少见的间叶源性肿瘤，乏脂肪型无特征性脂肪成分，影像学易与肝细胞肝癌等富血供病变混淆；结合临床无慢性肝病背景、实验室检查正常及典型富血供影像学表现，可提高术前诊断提示性，病理及免疫组化是确诊的金标准。

Abstract: Objective: To investigate the imaging features, pathological characteristics and differential diagnosis points of hepatic perivascular epithelioid cell tumor (hepatic PEComa), and to improve the imaging diagnostic level of this rare tumor. Methods: The medical records of a patient with hepatic PEComa confirmed by surgical pathology and immunohistochemistry were retrospectively analyzed. The examination methods and imaging findings of CT and MRI were described in detail, and compared with the pathological results. The clinical, imaging and pathological characteristics were summarized in combination with relevant literatures. Results: The patient was a 51-year-old female with no obvious clinical symptoms, and the results of tumor markers and hepatitis-related indicators in laboratory examinations were all normal. Imaging examination revealed a solitary nodule in the caudate lobe of the liver: the lesion showed a hypodense shadow on plain CT scan, with significant heterogeneous enhancement in the arterial phase of enhanced scan, and partial washout in the portal venous and delayed phases; on MRI, the lesion presented long T1 and long T2 signals, high signal on DWI but no reduction in ADC value, significant heterogeneous enhancement in the arterial phase of enhanced scan, partial washout in the portal venous and transitional phases, and low signal in the hepatobiliary specific phase, with no capsule and no obvious lipid components in the lesion. The diagnosis of hepatic PEComa was confirmed by postoperative pathology and immunohistochemistry, which showed diffuse positive expression of HMB45 and Melan-A, positive expression of SMA, negative expression of Desmin, etc. Conclusion: Hepatic PEComa is a rare mesenchymal tumor of the liver. The fat-poor type has no characteristic fat components, and its imaging manifestations are easily confused with those of hypervascular lesions such as hepatocellular carcinoma (HCC). Combining with the clinical background of no chronic liver disease, normal laboratory examinations and typical hypervascular imaging manifestations can improve the suggestive value of preoperative diagnosis, and pathology combined with immunohistochemistry is the gold standard for definite diagnosis.