Imaging of inflammatory pseudotumors of the liver

Purpose. To describe the imaging features of inflammatory pseudotumors of the liver. Introduction. Inflammatory pseudotumors of the liver are rare benign lesions that may simulate malignancy on imaging studies. Diagnosis is most frequently confirmed after surgical resection of the lesion. Materials and Methods. Retrospective study from 1998 to 2006 of histologically proven cases of inflammatory pseudotumors of the liver. A combination of the following imaging modalities were utilized: US, contrast enhanced US, helical CT and MRI. Results. A total of seven lesions (mean diameter of 61.4 mm) were detected in 6 patients (mean age of 66 years). Clinical and laboratory results were non-specific. The following imaging studies were available: US in 5 cases, including one with contrast material, CT in 5 cases and MRI in 3 cases. All tumors were hypoechoic on US, with no enhancement after injection of Levovist((R)). The tumors were generally hypodense on noncontrast CT and enhancement, when present,was delayed and moderate. On MRI, the tumors were iso- or slightly hyperintense on T2W images and iso- or slightly hypointense on T1W images with subtle peripheral enhancement on delayed imaging. Conclusion. The differential diagnosis of inflammatory pseudotumors of the liver should be known to radiologists and could be suggested in a clinical context of chronic inflammatory process in patients with nonspecific liver mass showing imaging features of partial fibrosis with delayed enhancement.