Inflammatory pseudotumor of the liver

Inflammatory pseudotumor of the liver: report of eight cases, including three unusual cases, and a literature review

BACKGROUND

Inflammatory pseudotumor (IPT) of the liver is a rare but increasingly recognized tumor-like lesion. This condition is becoming an important differential diagnosis in patients with hepatic space-occupying lesions. This study reports the clinical features of eight cases of IPT of the liver, including the first report of three cases with an unusual associated disease or clinical course.

METHODS

The study sample included cases of IPT diagnosed based on the histopathology in our institution from 1995 to 2004. Clinical events were reported and compared with reports in the literature.

RESULTS

The age of the patients ranged from 28 to 78 years. The most common symptoms were abdominal pain, fever and bodyweight loss. Three patients were diagnosed incidentally. The initial clinical diagnoses were hepatocellular carcinoma in three cases, liver abscess in two cases, metastasis in one case and uncertain nature in two cases. Two cases were associated with preceding endophthalmitis and cholangiocarcinoma, respectively. Two patients had spontaneous lesion regression, but one of these had possible recurrence 10 months later. The other two patients experienced resolution of their lesions following antibiotic treatment. Four patients underwent surgical resection with subsequent recovery.

CONCLUSIONS

The clinical and imaging features of IPT in this small series were found to sometimes mimic those of malignant liver tumors or abscess. Surgical resection was performed in half of the cases. However, IPT of the liver could resolve spontaneously or following antibiotics treatment.

Spontaneous regression of hepatic inflammatory pseudotumor with primary biliary cirrhosis: Case report and literature review

Hepatic inflammatory pseudotumor (IPT) is a rare benign non-neoplastic lesion characterized by proliferating fibrous tissue infiltrated by inflammatory cells. The exact etiology of IPT remains unclear. Although the association of IPT with systemic inflammatory disorders has been well established, a specific relationship with cholangitis is distinctly rare. We report a case of spontaneous regression of hepatic IPT with primary biliary cirrhosis (PBC). To date, only two cases of IPT with PBC have been reported. In our case, however, IPT developed during the course of improvement of cholangitis of PBC induced by effective treatment, differing from two previously reported cases. Our case indicates that the development of IPT does not also relate to the activity of cholangitis and/or hyper gamma-globulinemia, since our case was confirmed radiologically to be free of IPT when biliary enzymes and immunoglobulins were much higher than the corresponding values on admission. Comparison of our case with the two previously reported cases suggests that IPT occurring with PBC does not represent the same disease entity or be a bystander for PBC.

Duct-penetrating sign at MRCP: usefulness for differentiating inflammatory pancreatic mass from pancreatic carcinomas

PURPOSE

To define the duct-penetrating sign at magnetic resonance (MR) cholangiopancreatography (MRCP) and to assess the usefulness of this sign for distinguishing an inflammatory pancreatic mass (IPM) from a conventional pancreatic carcinoma (CPC) compared with arterial phase computed tomography (hereafter, CT) and arterial phase MR imaging (hereafter, MR imaging).

MATERIALS AND METHODS

MRCP, CT, and MR images were compared by means of receiver operating characteristic (ROC) analysis for 11 IPMs and 43 CPCs. With the MRCP images, a morphologic classification of the main pancreatic duct (MPD) was attempted for all lesions. On the basis of this classification and the enhancement patterns of a lesion, all readers graded the presence of IPM or CPC on a five-point scale for all images.

RESULTS

On the MRCP images, the morphologic characteristics of the MPD were nonobstruction for IPM (28 of 33, 85%) and obstruction or irregular stenosis for CPC (124 of 129, 96%). At ROC analysis among all the techniques, MRCP images had the highest value (0.98) for significant areas under the ROC curve (CT, 0.84; MR, 0.76) (P <.001). For the duct-penetrating sign in the broad sense (nonobstructed MPD) and the sign in the narrow sense (only normal MPD), the sensitivity, specificity, and accuracy for diagnosis of IPM were 85%, 96%, and 94%, respectively, and 36%, 100%, and 87%, respectively.

CONCLUSION

The duct-penetrating sign on MRCP images was more helpful to distinguish IPM from CPC than were the enhancement patterns on CT and MR images.

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 and 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.

Imaging of follicular dendritic cell tumours of the liver

Follicular dendritic cell tumour of the liver is a recently recognized entity. To date, only two cases have been described, both in the pathology literature. Histologically, it resembles an inflammatory pseudotumour and immunohistochemical and ultrastructural studies are required for its diagnosis. The ultrasound, computed tomography and angiographic features of two cases of follicular dendritic cell tumour of the liver are described in detail. One of the patients had multiple recurrences of this tumour. The imaging features are very similar to those of hepatocellular carcinoma. As follicular dendritic cell tumour is considered to be of low-grade malignant potential, in contrast to the dismal prognosis for hepatocellular carcinoma, it is important to be able to accurately distinguish between the two types of tumour prior to initiating definitive therapy.