Inflammatory pseudotumor of the liver: ferumoxide-enhanced MR imaging as a tiebreaker

Magnetic resonance imaging of inflammatory pseudotumor of the liver: a 2021 systematic literature update and series presentation

PURPOSE

Inflammatory pseudotumors of the liver (IPTL) are not exceptional benign lesions with various etiologies, histology, and imaging appearances. The incomplete knowledge of this pathology and the wide polymorphism sometimes resembling malignancy often induce long and expensive diagnostic flow, biopsy and occasionally unnecessary surgery. We propose a systematic revision of MRI literature data (2000-2021) with some narrative inserts and 10 new complete MRI cases, with the aim of organizing the data about IPTL and identifying some typical features able to improve its diagnosis from imaging.

METHODS

We performed a systematic revision of literature from 2000 to 2021 to obtain MRI features, epidemiological, and clinical data of IPTL. The basic online search algorithm on the PubMed database was "(pseudotumor) AND (liver) AND (imaging)." Quality assessment was performed using both scales by Moola for case report studies and by Munn for cross-sectional studies reporting prevalence data. A case-based retrospective study by collecting patients diagnosed with IPTL from three different university hospitals from 2015 to 2021 was done as well. Only cases with MR examinations complete with T1/T2/contrast-enhanced T1/Diffusion-Weighted (W) images and pathology-proven IPTL were selected.

RESULTS

After screening/selection 38 articles were included for a total of 114 patients. In our experience we selected 10 cases for a total of 16 IPTLs; 8 out of 10 patients underwent at least 1 MRI follow-up. Some reproducible and rather typical imaging findings for IPTL were found. The targetoid aspect of IPTL is very frequent in our experience (75% on T1W, 44% on T2W, 81% on contrast-enhanced T1W (at least one phase), 100% on Diffusion-W images) but is also recurrent in the literature (6% on T1W, 31% on T2W, 51% on CE-T1W (at least one phase), 18% on Diffusion-W images, and 67% on hepatobiliary phase). In our experience, Apparent Diffusion Coefficient map values were always equal to or higher than those of the surrounding parenchyma, and at MRI follow-up, nodule/s disappeared at first/second control, in six patients, while in the remaining 2, lesions persisted with tendency to dehydration.

CONCLUSION

A targetoid-like aspect of a focal liver lesion must raise diagnostic suspicion, especially if IgG4-positive plasma is detected. MRI follow-up mainly shows the disappearance of the lesion or its reduction with dehydration.

Two pseudotumor cases mimicking liver malignancy

Inflammatory pseudotumor of the liver is a rare benign tumor that can be confused with malignant tumors of the liver. It is usually diagnosed after pathologic evaluation of the resected lesion. If a mass lesion in the liver is suspicious for malignancy on radiologic evaluation then surgical resection is planned for suitable patients rather than a biopsy. Inflammatory pseudotumors are similar to malignant tumors on macroscopic assessment, but microscopically they are characterized by the presence of inflammatory cells. In case of clinical or radiologic suspicion, the lesion is biopsied and once the diagnosis of inflammatory pseudotumor is made the lesion is managed by conservative-medical treatment. It must be kept in mind as part of differential diagnosis to avoid unnecessary surgery.

Hepatic inflammatory pseudotumor: A case series

INTRODUCTION

Inflammatory pseudotumor (IPT) is a rare lesion consisted of inflammatory and myofibroblastic cells. These lesions may be found in different organs. There are less than 300 described cases.

PRESENTATION OF CASE

Case 1. 64-year-old cirrhotic male with a palpable epigastric mass. CT showed a lesion in liver segments 2 and 3 and left hepatic artery aneurism. Percutaneous embolization and wide spectrum antibiotics were tried, however the lesion grew. Left lateral hepatectomy was performed, and HIPT diagnosed. The patient died due to multiple organ dysfunction. Case 2. 30-year-old male with abdominal pain and fever. CT showed a hepatic hilar lesion. Surgical resection was performed after an ineffectual antibiotic trial, and HIPT was confirmed. The patient is doing well. Case 3. 73-year-old female with abdominal pain and fever. CT showed a 7cm lesion in the left liver lobe. Unrewarding cancerous screening was performed, and unsuccessful antibiotic course was tried. Resection was performed, and HIPT diagnosed. The patient is doing well. Case 4. 50-year-old cirrhotic male with abdominal pain. CT showed a segment 6 lesion and portal vein thrombosis. Considering cancer as the first hypothesis and the MELD score of 9, segmentectomy was performed. HIPT was the final diagnosis. The patient died due to abdominal sepsis.

DISCUSSION

HIPT is a lesion with a vast list of differential diagnosis. Antibiotics are the first line of therapy, although surgery is often necessary. Overall prognosis is good, although comorbidities may worsen it.

CONCLUSION

HIPT is a rare and misleading entity.

Capsular retraction: an uncommon imaging finding in hepatic inflammatory pseudotumour

Capsular retraction is an infrequent but characteristic feature of malignant liver lesions such as hepatic metastases and intrahepatic cholangiocarcinoma. Rarely, this finding may be observed in association with benign lesions, such as atypical haemangiomas. Capsular retraction has not previously been reported in association with hepatic inflammatory pseudotumour (IPT). Hepatic IPT is an uncommon benign hepatic lesion with a good clinical prognosis. In this report, we discuss the case of a 48-year-old woman with capsular retraction secondary to multifocal hepatic inflammatory IPTs.

Inflammatory pseudotumour of the liver: the residuum of a biliary cystadenoma?

Inflammatory pseudotumour is a rare form of a liver mass. We report the case of a 28-year-old man presenting with obstructive jaundice, in whom an inflammatory pseudotumour arose with the resolution of a mucus secreting cystic liver lesion. The initial features suggested an intrahepatic cystadenoma or cystadenocarcinoma, which on its involution left a solid mass. Histopathology showed an inflammatory pseudotumour with no evidence of malignancy. A similar case has been reported recently, with the development of an inflammatory pseudotumour following collapse of a liver cyst seen on imaging. These two cases may shed some light on the origins of these rare liver lesions.

Intrahepatic cholangiocarcinoma mimicking hepatic inflammatory pseudotumor

A 50-year-old male with hepatitis B was referred for a small intrahepatic nodule. Magnetic resonance images raised strong suspicion of a benign lesion, such as an inflammatory pseudotumor, while the other radiological studies were equivocal. Furthermore, the high-intensity image on diffusion magnified-weighted imaging with a low B value strongly suggested a benign tumor. In spite of the absence of typical clinical or radiological findings, needle biopsy revealed an intrahepatic cholangiocarcinoma (ICC). The diagnosis of peripheral ICC rich in fibrous tissue seems to require needle biopsy for pathological examination with immunohistochemical staining because it frequently mimics other diseases, including benign tumors.

Inflammatory pseudotumor of the liver masquerading as hepatocellular carcinoma after a hepatitis B virus infection: Report of a case

We report a rare case of hepatic inflammatory pseudotumor (IPT) after a hepatitis B virus (HBV) infection. Early contrast enhancement on computed tomography (CT) with a washout phenomenon at the delayed phase, and depleted Kupffer cell function on superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance imaging (MRI) suggested hepatocellular carcinoma (HCC). However, the lack of a tumor capsule, absence of liver cirrhosis, and normal serum levels of alpha-fetoprotein and PIVKA-II (protein induced by vitamin K absence; descarboxyprothrombin) contradicted this diagnosis. We excised the tumor to exclude malignancy, and the histopathological diagnosis was IPT. Recent evidence suggests that this entity has changed from an extremely rare pathology to an established disease. Thus, IPT should be considered in the differential diagnosis of a liver mass with an infectious-inflammatory antecedent. Although surgery is not mandatory, surgical removal is recommended if there is a possibility of malignancy. Further investigations are warranted to elucidate the mechanisms of IPT developing after an HBV infection.

Isolated hepatic involvement of cat scratch disease in immunocompetent adults: Enhanced magnetic resonance imaging, pathological findings, and molecular analysis--two cases

Visceral involvement in absence of lymphadenopathy is a rare manifestation in cat scratch disease; hepatic granulomas are rare, representing 0.3% of systemic manifestations of cat scratch disease, and gallbladder extension is a singular case. The present article refers to 2 rare cases of visceral cat scratch disease in immunocompetent adults with hepatic granulomatous inflammation, caused by Bartonella henselae infection, with gallbladder involvement in 1 case and no lymphadenopathy. Histological features demonstrated the presence of inflammatory necrotizing granulomatous nonneoplastic process. Molecular studies (polymerase chain reaction) were performed to confirm the infectious etiology.