Comparison of clinical and MRI features of hepatic angiosarcoma and epithelioid hemangioendothelioma

Objective Differentiating hepatic epithelioid hemangioendothelioma (EHE) and angiosarcoma (AS), the two most common vascular tumors in the liver, is important due to disparities in their prognosis and treatment. We aimed to compare clinical and MRI features of the two tumors. Methods This retrospective study included patients with pathologically-confirmed AS or EHE who underwent MRI using gadoxetate disodium between 2008 and 2023. Two radiologists independently reviewed MR images. Wilcoxon rank sum and Fisher's exact tests were used to compare clinical and imaging features. Overall survival was compared using restricted mean survival time at 3 years. Results 32 patients with AS (18 women [56.3%]; median age, 68 years) and 38 with EHE (24 women [63.2%]; 51 years) were included. Patients with AS were generally older (81.3% >= 60 years; P < 0.001), had more frequent laboratory abnormalities (P <= 0.018), and poorer overall survival (11.2 vs. 31.8 months; P < 0.001) than those with EHE. On MRI, a large dominant mass accompanied by smaller nodules (14/32, 43.8%), often with ill-defined margins (15/32, 46.9%) was prevalent in AS; compared with nodules of similar sizes (24/38, 63.2%; P = 0.015) with well-defined margin (30/38, 78.9%; P = 0.002) in EHE. Cirrhotic appearance of the liver was more frequent in AS (62.5%, P < 0.001), along with decreased parenchymal enhancement on hepatobiliary phase (31.3%, P < 0.001) and ascites (37.5%, P = 0.010). AS frequently presented with avid enhancement of bizarrely-shaped foci, with a centrifugal enhancement pattern. In comparison, targetoid appearance was characteristic of EHE (78.9% on T2-weighted, 54.1% on diffusion-weighted, 65.8% on multiphase images) (P <= 0.002), with enhancement degree typically lower than that of the aorta. On hepatobiliary phase, all the AS exhibited hypointensity, while 39.5% of EHE showed targetoid appearance (P < 0.001). Conclusion Patients aged >= 60 years presenting with laboratory abnormalities, typically with a large dominant mass accompanied by smaller nodules, exhibiting avid, bizarre, and centrifugal enhancement-particularly in the cirrhotic-appearing liver-suggests the likelihood of AS over EHE.