Objective:To study the CT manifestations of malignant hepatic perivascular epithelioid cell carcinoma (PEComa).Methods:Clinical data of nine patients undergoing surgery with histologically confirmed malignant hepatic PEComa in Yueqing People's Hospital, Wenzhou People's Hospital, and Yongjia County People's Hospital from January, 2010 to June, 2022 were retrospectively collected, including two males and seven females with a median age of 47 (43, 56) years old. The CT findings, including tumor size, shape, boundary, density, and enhancement patterns, were analyzed.Results:CT scans showed that all nine tumors were single lesions. Five tumors were located in right liver lobe, three in left lobe, and one in caudate lobe. The median tumor diameter was 5.7 (range, 3.3-16.0 ) cm. In terms of tumor shape, three were round, four were quasi-circular, and two were irregular. Eight tumors had well-defined boundaries, while one was ill-defined. Nine tumors showed uneven densities and were lower than the adjacent liver parenchyma. Four tumors had a false capsule, one contained fatty tissue, and six had necrotic and cystic changes. In the arterial phase of contrast-enhanced CT scanning, two tumors showed moderate enhancement and seven showed significant enhancement. In the portal venous and delayed phases, enhancement decreased significantly in four cases, showing a " fast-in and fast-out" pattern. In four cases, the enhancement persisted, showing a " fast-in and slow-out" pattern. One case showed no enhancement in any phase but had a strip-like enhanced vessel inside the tumor. Five cases had significantly thickened vessels around the tumor.Conclusion:The CT manifestations of PEComa are as follows: round or quasi-circular lesions with well-defined boundaries, uneven low densities, significant enhancement in the arterial phase and rapid washout or persistent enhancement in the portal venous and delayed phases.

Objective:To explore the imaging features of hyperostosis frontalis interna (HFI).Methods:One hundred patients with clinically diagnosed HFI were enrolled from Department of Radiology, Yueqing People's Hospital and Department of Imaging, Wenzhou People's Hospital from January 2011 to December 2022. MRI alone was performed in 45 patients; MRI+DR was performed in 14, and MRI+CT was performed in 41. The imaging features of these patients were analyzed retrospectively.Results:In these 100 patients, 20 were with external hyperplasia, 51 with internal hyperplasia, and 29 with intermediate hyperplasia. External hyperplasia manifested as proliferating towards the diploe, enjoying clear boundary, uniform high signals of the hyperplastic inner plate and diploe on T1WI and T2WI, and high density of the hyperplastic inner plate and diploe on CT and DR. Internal hyperplasia manifested as proliferating towards the cranial cavity, enjoying wavy or nodular inner edges, non-uniform low signals of hyperplastic inner plate on T1WI and T2WI, and high density of the hyperplastic inner plate on CT and DR. Intermediate hyperplasia manifested as proliferating simultaneously towards the cranial cavity and diploe, enjoying thin and blurred diploe, uniform or non-uniform high signals of the hyperplastic inner plate and diploe on T1WI and T2WI, and non-uniform high density of the hyperplastic inner plate and diploe on CT and DR. Compressed and displaced brain parenchyma, reduced anterior cranial fossa volume, and narrowed subarachnoid space were noted in these 100 patients, including 47 patients with obvious frontal lobe brain tissue compression (depth of 3.0-17 mm, averaged [8.6±5.9] mm), 35 with lacunar cerebral infarction, 33 with subcortical arteriosclerotic encephalopathy, and 32 with varied degrees of cerebral atrophy.Conclusion:HFI is characterized by thickening and hardening of the bilateral frontal bone inner plates, with wavy, nodular or spindle-shaped inner edges, compressed brain tissues, and reduced anterior cranial fossa; these imaging features can help the definite diagnosis of HFI.