Biliary inflammatory pseudotumor (IPT) of the liver is a rare benign tumor of which radiographic images, such as biliary stricture and dilatation, resemble those of cholangiocarcinoma (CC). Although repeated biliary cytology via endoscopic nasobiliary drainage (ENBD) is performed for differential diagnosis, a correct diagnosis remains difficult. The present study describes the case of a 76-year-old female patient with chronic liver disease. During surveillance, intrahepatic CC was suspected by imaging analyses; however, the carcinoembryonic antigen and CA19-9 levels were within normal ranges. Percutaneous core needle biopsy was not performed due to technical reasons; however, a left lobectomy was performed based on the diagnosis of malignancy by ENBD bile cytology. A pathological examination of the resected liver demonstrated biliary IPT. Reflecting on the cytological diagnosis of this case, a multi-reviewer re-evaluation of the biliary cytology of this IPT case and 2 cases of well-differentiated CC was then performed, which demonstrated difficulty in distinguishing between them. On the whole, ENBD cytology can play a limited role in differentiation between benign and malignant bile strictures. Surgical indication should be carefully determined and percutaneous core needle biopsy may be warranted in patients with normal tumor marker levels.

This case report describes the clinical process of a patient with a history of nasopharyngeal carcinoma (NPC) who was initially misdiagnosed with a metastatic tumor, later confirmed to be an inflammatory pseudotumor (IPT). The patient was a 68-year-old male individual who was diagnosed with nasopharyngeal carcinoma 4 years ago. The condition was well controlled after regular radiotherapy and chemotherapy. One year ago, a solid mass was found in the left lateral lobe of the liver during routine follow-up. MRI suggested nasopharyngeal carcinoma metastasis. Later, MRI at Peking Union Medical College Hospital also suggested nasopharyngeal carcinoma metastasis. Intrahepatic cholangiocarcinoma was not excluded, and surgical treatment was recommended. Preoperative biopsy was recommended by the multidisciplinary team (MDT); however, the patient declined due to financial constraints and personal preference. The patient underwent laparoscopic left lateral hepatectomy and hilar lymph node dissection at the Affiliated Hospital of Chengde Medical College. Postoperative pathology showed dense infiltration of neutrophils, lymphocytes, and eosinophils, with no malignant components, consistent with an inflammatory pseudotumor. The diagnosis was further confirmed by pathological review and immunohistochemistry at Peking Union Medical College Hospital. The patient recovered well after the operation, and there was no recurrence during 1 year of follow-up. This case suggests that in patients with a history of malignant tumors, even when imaging is highly suspicious of tumors, we should still be vigilant for infectious lesions and avoid anchoring bias. Preoperative biopsy and multidisciplinary comprehensive evaluation (MDT) can help clarify the diagnosis and reduce misdiagnosis and overtreatment.

IgG4-related cholangitis (IRC) is a rare fibroinflammatory disease of the biliary tree and liver and presents the major hepatobiliary manifestation of IgG4-related systemic disease (IgG4-RD). IRC also includes the IgG4-related inflammatory pseudotumor of the liver and IgG4-related cholecystitis. IRC mimics other cholangiopathies such as primary sclerosing cholangitis or cholangiocarcinoma. IRC may be found in 30 to 60% of cases with type 1 autoimmune pancreatitis, the most frequent manifestation of IgG4-RD. The pathogenesis of IRC (and IgG4-RD) is incompletely understood. Genetic predisposition, environmental factors, oligoclonal glucocorticosteroid-sensitive expansion of IgG4+ B cells/plasmablasts in blood and affected tissue and blocking autoantibody formation against protective IgG4-specific autoantigens such as annexin A11 and laminin 511-E8 with impaired protection of biliary epithelia against toxic bile acids have been described in IRC. Specific T cell subtypes are involved in the inflammatory process. The diagnosis of IRC is made according to HISORt criteria comprising histopathology, imaging, serology, other organ manifestations, and response to therapy. Treatment of IRC aiming to prevent organ failure and improve symptoms includes remission induction with highly effective glucocorticosteroids and long-term maintenance of remission with immunomodulators such as glucocorticosteroid sparing additives or B cell depleting approaches.

An inflammatory pseudotumor of the liver is a rare tumor-like lesion composed of polymorphous inflammatory cell infiltrates and variable amounts of fibrosis that can often mimic a malignant liver neoplasm. The etiology of inflammatory pseudotumors of the liver is unknown; symptoms are faint and imaging non-specific. Thus, it is often hard to make a diagnosis preoperatively and it is not so rare to over-treat patients with this disease or vice versa. Thus, more profound knowledge is necessary to plan appropriate disease management. We reported our two cases and systematically searched the literature regarding IPTL. We selected articles published in English from four databases, PubMed, Scopus, Web of Science and Google Scholar, and we included only articles with consistent data. Twenty nine papers fulfilling criteria for the review were selected. The analysis of 69 cases published from 1953 confirmed that the risk factors are unclear, the imaging data is not specific, and biopsy is crucial but not so widely used in clinical practice due to the procedure's related risks, and relatively low effectiveness and improvement in imaging analysis. Regarding treatment, surgeons have moved towards a more conservative attitude over the years due to better imaging quality and patient surveillance. However, surgery remains the modality of choice for most cases with an indeterminate diagnosis. Even if an inflammatory pseudotumor of the liver is a benign tumor with a good prognosis, not requiring any treatment in most cases, sometimes it remains challenging to differentiate it from ICC; therefore, there is a solid recommendation to manage this condition with a multidisciplinary team.