Intrahepatic bile duct rupture associated with IgG4-related sclerosing cholangitis presenting hepatic inflammatory pseudotumor

Clinical and Multimodal Imaging Features of Hepatic Inflammatory Pseudotumors: A Two-Center Retrospective Study

OBJECTIVES

Current literature on imaging characteristics of hepatic inflammatory pseudotumor (HIPT) is limited. This study aimed to analyze the contrast-enhanced ultrasound (CEUS) features in HIPT and compare them with contrast-enhanced computed tomography (CECT) and contrast-enhanced magnetic resonance imaging (CEMRI).

METHODS

A total of 83 patients with histologically proven HIPT from two medical institutions were included in this study. All patients underwent CEUS within 1 week before surgery or biopsy. Some patients received additional CECT or CEMRI. B-mode ultrasound (BMUS) features, enhancement parameters of CEUS, CECT and CEMRI were analyzed. Chi-square test was used to compare the enhancement patterns and diagnostic sensitivity between CEUS and CECT/CEMRI.

RESULTS

On the BMUS, HIPT mainly appeared hypoechoic (83.5%, 66/79), irregular shapes (62.0%, 49/79), heterogeneous echogenicity (72.2%, 57/79), and unclear boundary (65.8%, 52/79). A total of 61.5% (51/83) lesions exhibited mild hyper- or iso-enhancement in the arterial phase (AP), 59.0% (49/83) lesions had internal nonenhanced areas, and most lesions (71.1%, 59/83) showed early wash-out (<60 seconds) on the CEUS. There were significant differences between CEUS and CECT/CEMRI in enhancement intensity of AP and wash-out pattern (P < .05). The sensitivity in the diagnosis of HIPT among the three had no statistical difference (P>.05).

CONCLUSIONS

The CEUS features of HIPT lesions typically include mildly hyper-enhanced or iso-enhanced in AP, rapid wash-out in PVP, and often small nonenhanced areas within the mass. Furthermore, the wash-out pattern of CEUS and CECT/CEMRI are inconsistent, more akin to cholangiocarcinoma. The diagnostic efficacy of the three modalities is similar.

A case report of IgG4-related hepatic inflammatory pseudotumor in a 3-year old boy

Background

Hepatic Inflammatory Pseudotumor (IPT) is an infrequent condition often masquerading as a malignant tumor, resulting in misdiagnosis and unnecessary surgical resection. The emerging concept of IgG4-related diseases (IgG4-RD) has gained widespread recognition, encompassing entities like IgG4-related hepatic IPT. Clinically and radiologically, corticosteroids and immunosuppressive therapies have proven effective in managing this condition.

Case Presentation

A 3-year-old Chinese boy presented to the clinic with an 11-month history of anemia, fever of unknown origin, and a tender hepatic mass. Blood examinations revealed chronic anemia (Hb: 6.4 g/L, MCV: 68.6 fl, MCH: 19.5 pg, reticulocytes: 1.7%) accompanied by an inflammatory reaction and an elevated serum IgG4 level (1542.2 mg/L). Abdominal contrast-enhanced computed tomography unveiled a 7.6 cm low-density mass in the right lateral lobe, while magnetic resonance imaging demonstrated slight hypointensity on T1-weighted images and slight hyperintensity on T2-weighted images, prompting suspicion of hepatic malignancy. A subsequent liver biopsy revealed a mass characterized by fibrous stroma and dense lymphoplasmacytic infiltration. Immunohistochemical analysis confirmed the presence of IgG4-positive plasma cells, leading to the diagnosis of IgG4-related hepatic IPT. Swift resolution occurred upon initiation of corticosteroid and mycophenolate mofetil therapies.

Conclusion

This study underscores the diagnostic approach to hepatic IPT, utilizing histopathology, immunostaining, imaging, serology, organ involvement, and therapeutic response. Early histological examination plays a pivotal role in clinical guidance, averting misdiagnosis as a liver tumor and unnecessary surgical interventions.

IgG4-related hepatic inflammatory pseudotumor in a patient with serum IgG4-negative type 1 autoimmune pancreatitis

IgG4-related disease (IgG4-RD) can cause heterogeneous lesion in various organs. Serum IgG4 levels are useful in monitoring patients with IgG4-RD; however, when it is negative, more careful observation is required. A 58-year-old woman who had been diagnosed with serum IgG4-negative type 1 autoimmune pancreatitis (AIP) 3 years prior visited our hospital for the evaluation of a liver tumor. She had visited a nearby hospital 1 month prior with complaints of a swelling in her right neck, and histological examinations were suggestive of IgG4-related sialadenitis. A positron emission tomography scan showed fluoro-deoxy-glucose accumulation in her right liver lobe; therefore, she was referred to our hospital. Liver tumor biopsy showed inflammatory cell infiltration and storiform fibrosis, without histological findings indicative of a malignancy. Many IgG4-positive cells were detected in immunostaining; thus, an IgG4-related hepatic inflammatory pseudo-tumor was diagnosed. After increasing in steroid dosage, the patient remained recurrence-free with 2 years. To our knowledge, this is the first report of mass-forming IPT for serum IgG4-negative type 1 AIP. Occasionally, IgG4-related IPT may appear in the periphery of the liver, and serum IgG4-negative cases should be more carefully observed because serum IgG4 is not an indicator.

Incidental Finding of Hepatic Inflammatory Pseudotumor Immunoglobulin G4-Related Disease With Underlying Chronic Hepatitis C

Immunoglobulin G4-related disease (IgG4-RD) is a unique immunological disease that can impact multiple organs including a formation of a hepatic inflammatory pseudotumor (IPT). We present a case of a 67-year-old male with a history of chronic viral hepatitis C infection who had an accidental finding on magnetic resonance imaging (MRI) of a liver arterially enhancing lesion. With an extensive work-up, immunohistochemical stains for immunoglobulin G of the liver lesion was performed and showed markedly increased IgG4-positive plasma cells (> 50/HPF), which was consistent with hepatic inflammatory pseudotumor related to IgG4-RD. The patient was treated with prednisone with a complete resolution of the hepatic lesion. The diagnosis of hepatic IPT and IgG4-RD requires a high degree of clinical suspicion and coordination with a multi-disciplinary team, including pathologists. Early tissue acquisition and staining for IgG4 was essential for the early diagnosis and treatment in this case. We also provide a comprehensive summary of published reports of IgG4-RD presenting with IPT.

A Case of Hepatic Immunoglobulin G4-Related Disease Presenting as an Inflammatory Pseudotumor and Sclerosing Cholangitis

An inflammatory pseudotumor is a benign disease characterized by tumor-like lesions consisting of inflammatory cells including plasma cells and fibrous tissue. Recently, some inflammatory pseudotumor cases proved to be a form of Immunoglobulin G4-related disease (IgG4-RD). This novel clinical entity, recognized as a fibroinflammatory condition, is characterized by lymphoplasmacytic infiltration with a predominance of IgG4-positive plasma cells, storiform fibrosis, and often elevated serum IgG4 concentrations. We report a case of IgG4-RD in the form of an inflammatory pseudotumor in the liver with combined sclerosing cholangitis. We recommend that for diagnosing IgG4-RD accurately, it is important to obtain adequate tissue samples and follow-up the lesion in clinical practice.