MRI and pathological features of hilar schwannomas: an analysis of 5 cases / 中华肝胆外科杂志

ABSTRACT

Objective:To analyse the MRI features of hilar schwannomas and pathology.Methods:The MRI and pathological features of 5 patients with hilar schwannomas which were confirmed histopathologically at Zhongshan Hospital, Fudan University from January 2012 to August 2019 were retrospectively analyzed. There were 3 males and 2 females, with age ranging from 47 to 67 years (median age 59 years). Contrast-enhanced MRI scans were performed in these 5 patients. The site, shape, size, edge, signal and enhancement pattern of these lesions and pathologicl findings were analysed.Results:All the lesions were single, located in and around the perihilar region. Four lesions were oval or roundish, and 1 lesion was sausage-shaped. Two lesions were solid while 3 lesions were cystic solid. All lesions had clear borders with intact capsules. The solid parts in all the lesions showed isointensity or slightly hypointensity on T 1 weighted imaging, hyperintensity on fat-suppression T 2 weighted imaging (T 2WI), hyperintensity on diffusion weighted imaging, slightly hyperintensity / isointensity / slightly hypointensity on apparent diffusion coefficient maping with progressive mild to moderate enhancement. Thick septum was observed in the cystic part. The septum and capsule showed mild to moderate delayed enhancement. Fluid-fluid level was seen in one lesion. The cystic solid lesion in one patient showed the " target sign" on fat-suppression T 2WI. All the 5 tumors were close to blood vessels, and their long axes followed the shape of the portal vein. In 1 patient, the lesion slightly compressed the adjacent bile ducts. Pathological examination showed that all the tumors in the 5 patients had complete fibrous envelopes, and the solid parts of the tumor showed mainly spindle cells. Conclusions:The MRI features of hilar schwannomas were oval or sausage-shaped lesions, with the long axis along the portal vein. They were prone to develop cystic changes, and a"target sign"could be shown on fat-suppression T 2WI. The solid parts, septa and capsules of the lesions showed mild to moderate progressive enhancement after contrast-injection.