Abstract: Objective:To analyze and summarize the imaging features of hepatic epithelioid hemangioendothelioma (EHE).
Methods:The retrospective and descriptive study was conducted. The clinicopathological data of 9 patients with EHE who were admitted to the Cancer Hospital of Chinese Academy of Medical Sciences between June 2012 and June 2016 were collected. Patients underwent computed tomography (CT) and magnetic resonance imaging (MRI) examinations. Number, size, location, shape, density or signal and enhancement method of lesions, with or without lesions fusion and relationship between lesions and vessels were analyzed by 2 imaging doctors. Lesions in left lobe of liver, right lobe of liver and caudate lobe of liver were respectively counted. Real number was a standard as less than 5 lesions and more than or equal to 5 lesions was represented as ≥5. Observation indicators: (1) overall imaging features of EHE; (2) MRI findings of EHE; (3) CT findings of EHE; (4) treatment and pathological features of EHE and results of followup. Patients received the corresponding treatment after imaging examinations. Followup using outpatient imaging examinations was performed to detect tumor recurrence and stable condition of patients up to December 2016.
Results:(1) Overall imaging features of EHE: of 9 patients with EHE, 6 received plain and enhanced scans of MRI, 3 received plain and enhanced scans of CT (1 combined with MRI), 1 received enhanced scan of CT. Lesions in right lobe of liver were more than that in left lobe of liver, and there were fewest lesions in caudate lobe of liver. Lesions were round or similarround shape, with a maximum diameter of 2.5-6.1 cm and an average diameter of 3.6 cm. Four patients had total 2-5 lesions and less than 5 lesions in each lobe of liver, without lesions fusion, including 1 with “halo” sign and “capsule retraction” sign and 1 with “halo” sign. Of other 5 patients, 2 had more than or equal to 5 lesions in each lobe of liver and 3 had more than or equal to 5 lesions in 2 lobes of liver; 4 had “halo” sign, “lollipop” sign, “capsule retraction” sign and a tendency of lesions fusion, 1 had “halo” sign and “capsule retraction” sign. The “halo” sign, “lollipop” sign, “capsule retraction” sign and a tendency of lesions fusion were 7/9, 4/9, 6/9 and 4/9 in 9 patients, respectively. (2) MRI findings of EHE: 6 patients received plain and enhanced scans of MRI. ① Four patients had clear “halo” sign on T2 weighted imaging (T2WI), in portal vein phase and hepatobiliary phase. Three patients had slightly central hyperintensity and thick ring of slightly peripheral hyperintensity on T2WI. There were slightly central hyperintensity and thin ring of slightly peripheral hypointensity in 1 patient, and the “halo” sign was seen by enhanced scan. There were central hyperintensity and peripheral hypointensity in 2 patients, and the “halo” signs were clearly seen in hepatobiliary phase. Some patients were combined with multiple manifestations. ② There were no obvious “halo” sign on T2WI, annular enhancement in arterial phase by enhanced scan, no obvious “halo” sign in portal vein phase and hepatobiliary phase in 2 patients. There were hypointensity on T1WI and isointensityhyperintensity on DWI in 6 patients. (3) CT findings of EHE: plain scan of CT in 4 patients showed slightly hypodense shadow, without calcification. Enhanced scan of CT in 3 patients showed that obvious halolike enhancement was seen in portal vein phase and halo rings were less obvious than that by MRI examination. (4) Treatment and pathological features of EHE and results of followup: of 9 patients with EHE, 4 underwent surgical resection based on lesions ≤5 and surgical specimens were detected by pathological examination, 5 underwent interventional treatment and pathologic examination with biopsy. Gross specimen examination showed that lesions were solid and stiff, with greyish white section plane and infiltrative margin. Tumor cells consisted of epithelioid cells under the microscopy, without atypia and with rare mitotic figures, and vacuoles were seen in cytoplasm. Immunohistochemistry showed CD31 and CD34 were positive. Nine patients were followed up for 6-54 months. During the followup, 4 patients with surgery had no recurrence and 5 patients with interventional therapy remained stable condition.
Conclusions:Imaging manifestations of hepatic EHE are the more typical when lesions of EHE became more. Hepatic EHE has a tendency of lesion fusion, “halo” sign, “capsule retraction” sign and “lollipop” sign. Imaging manifestations on T2WI with fat suppression, in portal vein phase and hepatobiliary phase are helpful to improve the diagnosis of hepatic EHE.