Inflammatory pseudotumors of the liver: experience of 114 cases

Case report: An inflammatory pseudotumor of the caudate lobe of the liver caused by a foreign body

This case report explores a rare foreign body-induced inflammatory pseudotumor in the caudate lobe of a 47-year-old male. The patient was admitted to the hospital due to epigastric pain and fever. Radiological examinations led to the diagnosis of a malignant tumor, and a resection of the caudate lobe lesion was performed. The excised tumor specimen revealed a fishbone-like foreign body. Immunohistochemistry suggested that this was an inflammatory pseudotumor rather than a malignant tumor. This prompted us to contemplate the origin of the foreign body and the mechanisms by which it led to the formation of the inflammatory pseudotumor.

Characteristics of imaging in hepatic inflammatory pseudotumors: a comparison between IgG4-related and IgG4-unrelated cases

OBJECTIVES

The objective of this study was to examine the imaging features of hepatic inflammatory pseudotumors (IPTs) associated with IgG4-related and IgG4-unrelated conditions and to enhance the approach toward distinguishing between these two types of IPTs.

METHODS

A retrospective study was conducted, involving 20 patients diagnosed with hepatic IPTs. Imaging procedures were conducted within a timeframe of 4 weeks prior to hepatectomy or biopsy. The imaging features were then analyzed and compared using chi-squared analysis.

RESULTS

Seventeen (81.0%) IPTs were located in the hepatic subcapsular area; six (66.7%) IgG4-related IPTs were distributed around the hepatic hilum; and eleven (91.7%) IgG4-unrelated and three (33.3%) IgG4-related IPTs had unclear boundaries. All lesions exhibited similar characteristics in CT scans, T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), and diffusion-weighted imaging (DWI), with the apparent diffusion coefficient (ADC) values slightly higher than the surrounding liver tissue. Delayed hypoenhancement, observed in five cases (55.6%), was exclusively present in IgG4-related IPTs. The remaining IPT lesions displayed progressive enhancement, septal and marginal enhancement, and persistent enhancement. Central enhancement was absent in three IgG4-related IPTs (33.3%) and ten IgG4-unrelated IPTs (83.3%). The duct-penetrating sign was identified in two IgG4-unrelated IPTs (16.7%) and seven IgG4-related IPTs (77.8%). Furthermore, seven patients with IgG4-related IPTs had additional lesions outside the liver.

CONCLUSIONS

IgG4-related lesions are frequently found in the vicinity of the hepatic hilum; they display the duct-penetrating sign and affect other organs as well. Both groups exhibited progressive or persistent contrast enhancement in typical IPT lesions, but delayed hypoenhancement was only observed in the IgG4-related IPT group. IgG4-unrelated IPT lesions often exhibited indistinct boundaries lacking central enhancement.

CRITICAL RELEVANCE STATEMENT

Differences in imaging features differentiate IgG4-related and -unrelated inflammatory pseudotumors (IPT). IgG4-related lesions are frequently near the hepatic hilum, display duct-penetrating sign, and affect other organs. Only the IgG4-related group demonstrated delayed hypoenhancement. IgG4-unrelated IPT lesions often exhibited indistinct boundaries lacking central enhancement.

KEY POINTS

Compared with IgG 4-unrelated IPTs, IgG4-related IPTs show delayed hypoenhancement and affect other organs. IgG4-unrelated IPTs have unclear boundaries and lack central enhancement. Improved IPT diagnostic capabilities can help minimize additional, potentially unnecessary, interventions.

Hepatic pseudotumor: A diagnostic challenge

Hepatic pseudotumors are rare lesions of unknown origin, characterized by the proliferation of fibrous connective tissue and inflammatory cell infiltrates. They mimic malignant lesions clinically, and radiologically, given their non-specific clinical and imaging features. The pathophysiology of hepatic pseudotumor is incompletely understood and there are no standardized criteria for diagnosis. Pseudotumors have been reported to develop in various organs in the body with the lung and liver being the most common site. Hepatic pseudotumors develop in patients with underlying triggers of liver inflammation and injury, including infections, autoimmune liver diseases, bile duct injury, or surgery. Hepatic pseudotumors respond well to conservative treatment with antibiotics, and steroids and some may regress spontaneously, thus avoiding unnecessary resection. This condition is rewarding to treat. It is important to recognize pseudotumor as a distinct clinical entity and include it in the differential of liver masses with atypical imaging features.

Hepatic Inflammatory Pseudotumor-Focusing on Its Heterogeneity

Hepatic inflammatory pseudotumors (IPTs) are defined as benign, non-malignant, non-metastasizing tumors characterized by the presence of myofibroblastic spindle cells, hetorogenous populations of inflammatory cells, particularly plasma cells, lymphocytes and macrophages, as well as locations of fibrosis and necrosis without cellular anaplasia or atypical mitoses. Despite subsequent reports in the references, hepatic IPT remains difficult to diagnose; while posing major issues specifically for its differential diagnosis compared with that of other various benign diseases and malignant hepatic tumors. Histopathological findings are always a requisite for confirming the diagnosis, particularly given that the pathogenesis of IPT remains ambiguous to date. Hepatic IPT is a heterogeneous entity in terms of its clinical features, pathological findings, and pathogenesis. Once the diagnosis is confirmed, however, needless surgery such as wedge resection and lobectomy should be avoided. Here, we discuss the heterogeneity of hepatic IPT, its clinical features, pathological findings, and pathogenesis, and describe its differential diagnosis.

Inflammatory Pseudotumor of the Liver

Hepatic inflammatory pseudotumor (IPT) describes a mass lesion composed of fibroblasts or myofibroblasts with a dense inflammatory infiltrate comprising lymphocyte, plasma cells, and histiocytes. These lesions are presumed to be an exuberant response to an infectious organism, although in most cases the causative agent is unknown. In specific circumstances, pathologists should consider ancillary techniques to exclude specific infections, such as mycobacteria, Candida, or syphilis. IgG4-related disease may cause a plasma-cell rich IPT. Finally, true neoplasms can mimic IPTs and must be excluded with appropriate ancillary studies, including inflammatory myofibroblastic tumor, follicular dendritic cell tumor, inflammatory angiomyolipoma, Hodgkin lymphoma, and inflammatory hepatocellular carcinoma.

Successful treatment with laparoscopic extended posterior sectionectomy for inflammatory pseudotumor in the liver with para-aortic lymphadenitis

Inflammatory pseudotumor (IPT) is a rare disease that requires a differential diagnosis from malignancies. We describe a case of hepatic IPT with para-aortic lymphadenopathy, treated with a stepwise strategy of laparoscopic surgery. A 61-year-old woman was referred with a liver lesion. Computed tomography revealed a 13 cm well-defined lesion in segments VII-VI. The patient also had bead-like enlarged lymph nodes from the perihilar to the para-aortic regions. Although percutaneous lymph node biopsy showed no evidence of malignancy, 18 F-fluorodeoxyglucose positron emission tomography revealed accumulation in the lesion and lymph nodes. Lymph nodes were harvested laparoscopically for intraoperative pathological examination. With no evidence of malignancy, laparoscopic liver resection was continuously performed as a diagnostic treatment. The patient was given a pathological diagnosis of IPT and was discharged on the 16th day and is well 2 years after surgery. The minimally invasive laparoscopic approach to diagnostic treatment could be useful with secure advantages.

Rare benign liver tumors that require differentiation from hepatocellular carcinoma: focus on diagnosis and treatment

BACKGROUND/AIM

Recently, an increase in the number of asymptomatic rare benign liver tumors (BLTs) has been reported during health check-ups. It is difficult to determine the nature of partial rare BLTs and not easy to distinguish from malignant liver tumors. This study aimed to analysis clinical features, diagnosis and treatment of rare BLTs to reduce misdiagnosis and provide reference for clinical practice.

METHODS

From January 2012 to January 2021, we treated 112 rare BLTs by hepatectomy, including 54 focal nodular hyperplasias, 14 hepatocellular adenomas, 28 hepatic angiomyolipomas, 3 hepatic granulomas, 2 inflammatory pseudotumors of the liver, 2 nodular regenerative hyperplasia, 2 hepatic lipomas, 1 solitary fibrous tumor of the liver, 1 hepatic schwannoma and 1 hepatic myelolipoma.

RESULTS

The majority of patients were middle-aged female and asymptomatic. Single tumors were dominant. The diagnostic accuracies of computed tomography (CT) and magnetic resonance imaging (MRI) were 32.5% and 44.2%, respectively. The majority of tumors were likely to be misdiagnosed as hepatocellular carcinoma (HCC) or difficult to distinguish from HCC. All patients underwent surgical treatment. Postoperative pathological and immunohistochemical examination can confirm the diagnosis. No patients without tumor recurrence or metastasis during follow-up period.

CONCLUSION

Altogether, the clinical symptoms of rare BLTs lack specificity, and their preoperative diagnosis largely depends on imaging examination, with a low diagnostic accuracy rate and high chances of misdiagnosis as HCC. Diagnosis is confirmed by pathological and immunohistochemical examination. Surgical resection for rare BLT is safe and effective, regular postoperative follow-up is necessary.

Multiple Inflammatory Pseudotumors of the Liver Demonstrating Spontaneous Regression: A Case Report

Inflammatory pseudotumor (IPT) of the liver is a rare benign disease. IPTs generally develop as solitary nodules, and cases with multiple lesions are uncommon. We herein report a case of multiple IPTs of the liver that spontaneously regressed. A 70-year-old woman with a 10-year history of primary biliary cholangitis and rheumatoid arthritis visited our hospital to receive a periodic medical examination. Abdominal ultrasonography revealed multiple hypoechoic lesions, with a maximum size of 33 mm, in the liver. Contrast-enhanced computed tomography revealed low-attenuation areas in the liver with mild peripheral enhancement at the arterial and portal phases. We first suspected metastatic liver tumors, but fluorodeoxyglucose positron emission tomography, magnetic resonance imaging and contrast-enhanced ultrasonography suggested the tumors to be inconsistent with malignant nodules. A percutaneous biopsy showed shedding of liver cells and abundant fibrosis with infiltration of inflammatory cells. Given these findings, we diagnosed the multiple tumors as IPTs. After careful observation for two months, the tumors almost vanished spontaneously. Physicians should avoid a hasty diagnosis of multiple tumors based solely on a few clinical findings, and a careful assessment with various imaging modalities should be conducted.

IgG4-related hepatic inflammatory pseudotumour: could MRI suggest the correct diagnosis?

We report a case of a 62-year-old woman, HIV positive, with a 3-week history of jaundice and elevated cholestatic enzymes. Imaging studies displayed intrahepatic biliary dilatation and a central liver lesion. Pathology described lesions of active cholangitis, lymphoplasmacytic infiltration and fibrosis, suggesting a hepatic inflammatory pseudotumour (IPT) IgG4 related. IgG4-related lymphoplasmacytic form of IPT belongs to IgG4-related diseases. We discuss the importance to include IgG4-related hepatic IPT as part of the differential diagnosis of any liver lesion, highlighting potential imaging clues that may help in establishing the correct diagnosis.

Inflammatory Myofibroblastic Tumor of the Porta Hepatis: A Case Report

A 43-year-old man presented with painless jaundice. Imaging revealed a porta hepatis mass compressing the common bile duct. Endoscopic biopsy was negative for malignancy. Complete surgical resection was performed. Pathological assessment showed IGg4 negative inflammatory myofibroblastic tumor.

Distinguishing Hepatocellular Carcinoma From Hepatic Inflammatory Pseudotumor Using a Nomogram Based on Contrast-Enhanced Ultrasound

BACKGROUND

Hepatocellular carcinoma (HCC) and hepatic iflammatory pseudotumor (IPT) share similar symptoms and imaging features, which makes it challenging to distinguish from each other in clinical practice. This study aims to develop a predictive model based on contrast-enhanced ultrasound (CEUS) and clinical features to discriminate HCC from IPT.

METHODS

Sixty-two IPT and 146 HCC patients were enrolled in this study, where pathological diagnosis served as the reference standard for diagnosis. Clinical and ultrasound imaging data including CEUS features: enhancement degree during arterial phase, portal phase and delayed phase, enhancement pattern, early washout within 60 s, feeding artery, peritumoral vessels, peritumoral enhancement, and margin of nonenhanced area were retrospectively collected. Imaging data were reviewed by two experienced ultrasound doctors. Patients were randomly assigned to training and validation sets. Chi-squared test followed by LASSO regression was performed on ultrasonographic features in the training set to identify the most valuable features that distinguish HCC from IPT, based on which the sonographic score formula was generated. With the significant clinical and ultrasonographic indicators, a nomogram was developed. The performance of the nomogram was verified by ROC curve and decision curve analysis (DCA) with the comparison with sonographic score and the ultrasound doctor's diagnosis.

RESULTS

The most valuable ultrasonographic features that distinguish between HCC and IPT were enhancement degree during arterial phase, early washout, peritumoral vessels, peritumoral enhancement, and liver background. The sonographic score based on these features was verified to be an independent factor that predicts the diagnosis (p = 0.003). Among the clinical indicators, AFP (p = 0.009) and viral hepatitis infection (p = 0.004) were significant. Sonographic score, AFP, and viral hepatitis were used to construct a predictive nomogram. The AUC of the nomogram was 0.989 and 0.984 in training and validation sets, respectively, which were higher than those of sonographic score alone (0.938 and 0.958) or the ultrasound doctor's diagnosis (0.794 and 0.832). DCA showed the nomogram provided the greatest clinical usefulness.

CONCLUSION

A predictive nomogram based on a sonographic signature improved the diagnostic performance in distinguishing HCC and IPT, which may help with individualized diagnosis and treatment in clinical practice.

Hepatic Inflammatory Pseudotumor: An Important Differential Diagnosis in Patients With a History of Previous Biliary Procedures

Hepatic inflammatory pseudotumors (IPTs) are rare lesions that mimic malignancy clinically, radiologically, and pathologically. The pathophysiology is unknown, and no criteria exist for diagnosis. This series includes 3 cases: 1 patient had recent biliary drainage with bile duct stent placement, and the other 2 patients had hepatic abscess formation before IPT development, which further supports that hepatic IPTs develop in patients with underlying triggers of liver inflammation and injury, including infections and/or bile leakage into the parenchyma. All 3 patients were successfully treated with antibiotics, sparing them surgical intervention. Follow-up showed complete resolution, and none developed recurrences or malignancies.

An inflammatory myofibroblastic tumor in the transplanted liver displaying quick wash-in and wash-out on contrast-enhanced ultrasound: A case report

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is an uncommon mesenchymal neoplasm, and its presence in a grafted liver is exceedingly rare.

PATIENT CONCERNS

A 54-year-old woman was admitted to our hospital with a half-month history of intermittent melena. She had undergone deceased-donor liver transplantation (LT) for hepatitis B virus related liver cirrhosis without hepatocellular carcinoma 5 months previously.

DIAGNOSIS

Laboratory examination showed impaired liver and renal functions and Epstein-Barr virus (EBV) infection, but tumor markers within normal ranges. Gastroscopy showed esophageal varices. Ultrasound and computed tomography angiography revealed an ill-defined and irregular solitary lesion in the porta hepatis, encasing both the portal vein and the hepatic artery. The lesion was characterized by arterial hyper-enhancement and hypo-enhancement in the remaining phases with contrast-enhanced ultrasound (CEUS). The lesion was finally confirmed as an IMT by ultrasound-guided biopsy.

INTERVENTION

The patient received conservative treatment, including immunosuppression, endoscopic variceal ligation, antibiotics, steroids, and antiviral agents.

OUTCOME

The patient's gastrointestinal bleeding was controlled, but the symptoms associated with portal hypertension worsened. Attempts to perform a transjugular intrahepatic portosystemic shunt were unsuccessful, and she unfortunately died soon after.

LESSONS

A differential diagnosis of IMT should be considered in LT recipients presenting with EBV infection, normal tumor markers, and a de novo hepatic lesion with quick wash-in and wash-out on CEUS. Ultrasound is associated with the advantages of convenience and nonionizing radiation, and should thus be the priority approach for monitoring transplanted liver.

Typical and atypical benign liver lesions: A review

Focal liver lesions are routinely encountered by clinical radiologists and represent a wide spectrum of pathology. Majority of these lesions are likely to be benign in nature, especially in the absence of chronic liver disease or primary cancer. A radiologist must be aware of common and uncommon imaging features of benign lesions across the various imaging modalities. This review discusses pathognomonic imaging features of common benign focal liver lesions seen on ultrasound, computed tomography and magnetic resonance, and adds to existing knowledge with the recent updates to have emerged in this area.