Abstract: Background and purpose: Hepatic epithelioid hemangioendothelioma (HEHE) is an extremely rare, vascularly original tumor, and would be misdiagnosed easily in the clinical and imaging characteristics. This study aimed to investigate the imaging features of HEHE and our experience in clinical diagnosis and treatment, and to provide important reference for the diagnosis and treatment of HEHE in the future. Methods: This study retrospectively analyzed clinical manifestations, imaging features, pathological characteristics and treatment effects of 5 HEHE cases confirmed by pathology at Department of Integrative Cancer, Fudan University Shanghai Cancer Center. Results: The ratio of male to female patients was 2 to 3. HEHE predominantly occurred in middle-aged female patients whose ages range from 26 to 65 (mean=45.6). Imaging features of HEHE included multifocal hepatic disease (n=2), systemic multi-center multi-tissue occurrence (n=3). The ultrasound images showed isoechoic or hypoechoic lesions with no obvious blood flow signal in the lesions. CT plain scan showed isointensity or hypointensity, while MR unenhanced with hypointense T1 signal and hyperintense T2 signal. The density or signal was uneven. Contrast-enhanced CT and MR images showed “slow in slow out”, obvious and variable degrees of peripheral rim enhancement. High FDG uptake showed delayed imaging characteristics (PET/CT). DSA angiography showed the tumor blood vessels were slim. After transcatheter arterial chemoembolization (TACE) surgery, lipiodol deposition within the lesion was not ideal. Under the microscope, tumor cells showed epithelial differentiation; angiogenesis was also visible. Immunohistochemistry staining showed CD31 and CD34 positive in all the 5 cases. Two cases treated with TACE combined with high intensity focused ultrasound (HIFU) and/or radiofrequency ablation (RFA) had good result. Conclusion: The clinical and radiological characteristics of HEHE are distinctive. Currently, for patients with systemic multi-organizational multi-center lesions, TACE combined with HIFU and/or RFA might be the most effective treatment method.

Key words: Liver neoplasm, Epithelioid hemangioendothelioma, Diagnosis, Transcatheter arterial chemoembolization, High intensity focused ultrasound, Radiofrequency ablation