Inflammatory pseudotumor of the liver in patients with recurrent pyogenic cholangitis: CT-histopathologic correlation

PURPOSE: To correlate computed tomographic (CT) features of inflammatory pseudotumors of the liver with histopathologic results in patients with recurrent pyogenic cholangitis. MATERIALS AND METHODS: CT features of 13 cases of inflammatory hepatic pseudotumor in 10 patients with recurrent pyogenic cholangitis were reviewed. Diagnosis was made by means of surgical resection in all patients. CT scans were analyzed for the appearance of masses and ancillary findings in correlation with the histopathologic findings in each resected specimen. RESULTS: The masses were 2.0-7.0 cm (mean, 3.5 cm). At nonenhanced CT, the masses appeared as ill-defined, hypoattenuating lesions. At-contrast material-enhanced CT, the masses exhibited central hypoattenuating areas with an iso- or hyperattenuating thickened periphery in four cases and a multiseptate appearance with hyperattenuating internal septa and periphery in nine cases. CT-histopathologic correlation showed that the central hypoattenuating area indicated the presence of chronic inflammatory infiltrates with foamy histiocytes, plasmacytes, and lymphocytes, while iso- or hyperattenuating areas in the periphery a nd internal septa of the mass represented fibroblastic proliferation. All patients had CT features of recurrent pyogenic cholangitis, such as hepatolithiasis, intrahepatic duct stricture and dilatation, common bile duct calculi, pneumobilia, or parenchymal atrophy. CONCLUSION: Although CT features are not specific, inflammatory pseudotumor should be included in the differential diagnosis in patients with recurrent pyogenic cholangitis and a hepatic mass detected at CT.