Ultrasound characteristics of hepatic epithelioid hemangioendothelioma: a multi-center case series study.

Aims: Hepatic epithelioid hemangioendothelioma (HEHE) is a rare vascular tumor that primarily affects the liver. This study aimed to analyze the characteristics of conventional ultrasound (US) and contrast-enhanced ultrasonography (CEUS) in HEHE.

Material and methods: This multi-center case series study enrolled patients diagnosed with HEHE from five hospitals in China between August 2004 and October 2022. Data on conventional US and CEUS characteristics were collected and analyzed.

Results: A total of 41 patients with HEHE were included, comprising 14 males and 27 females with a mean age of 50.62±11.43 years. The mean size of the lesion was 4.51±2.92 cm. Among these patients, 29 were confirmed through surgical resection and 12 through liver biopsy. Conventional US imaging identified three types of HEHE: multifocal type in 35 patients (85.4%), single nodular type in 1 patient (2.4%), and giant type in 5 patients (12.2%). US revealed proximity to the liver capsule in 29 patients (71%), hypoechoic appearance in 36 patients (88%), heterogeneity in 4 patients (10%), and hyperechoic appearance in 1 patient (2.4%). CEUS also demonstrated three distinct enhancement patterns: peripheral marginal enhancement with centripetal filling in the arterial phase and washout in the portal venous and venous phases (23 patients), eterogeneous enhancement in the arterial phase with washout in the subsequent phases (7 patients), and mild hyperenhancement in the arterial phase with resolution in later phases (9 patients). A hypo-enhancement pattern in the portal venous and venous phases was observed in 38 patients, suggesting a higher degree of malignancy.

Conclusion: HEHE exhibits specific US findings, primarilypresenting as multiple hypoechoic lesions distributed under the liver capsule.