Case Of Immunoglobulin G4-related Disease Research Articles

Imaging Findings in Cardiovascular Involvements of IgG4 Related Disease: A Systematic Review Study.

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition characterized by IgG4-positive plasma cell infiltration that can affect multiple organs, including the cardiovascular system. The diagnosis of IgG4-RD relies on a combination of clinical, serological, radiological, and pathological findings. However, due to the varied and insidious clinical presentations, normal IgG4 levels in a significant percentage of patients, and frequent multi-organ involvement, imaging plays a crucial role in the diagnosis of IgG4-RD. The aim of study is to comprehensively examine the imaging findings in IgG4-related cardiovascular disease for accurate diagnosis and appropriate treatment. A systematic search was conducted across electronic databases, PubMed, Scopus, and Web of Sciences, until 1 September 2023, following PRISMA guidelines by searching major databases for studies reporting detailed cardiovascular imaging findings in IgG4-RD. The search yielded 68 studies (60 case reports, 5 case series, 2 cross-sectional, 1 case-control) with 120 cases of cardiovascular IgG4-RD. Most of the cases were male, averaging 62.8 years. The common initial symptoms were dyspnea and chest pain. The most common imaging finding was vasculopathy, including vessel wall thickening, periarteritits, periaortitis, aortitis, stenosis, ectasia, aneurysm formation, intramural hemorrhage, fistula formation, and dissection, followed by pericardial involvement and mediastinal masses. Case series and cross-sectional studies also showed vasculopathy being the most common finding on various imaging modalities, including angiography and PET/CT, highlighting the complex pathology of IgG4-RD. This study evaluated current IgG4-RD articles, revealing a higher prevalence in men and vasculopathy as the most common cardiovascular complication.

A Case of Immunoglobulin G4-related Disease Complicated by Atopic Dermatitis Responsive to Upadacitinib Treatment.

Immunoglobulin G4-related disease is mainly treated with glucocorticoids. In many cases, this disease is resistant to glucocorticoids, and their toxicity can be a problem. We encountered a patient with immunoglobulin G4-related disease affecting multiple organs (such as the skin, lung, and lacrimal gland), who had comorbidities, including atopic dermatitis and diabetes. In this case, while glucocorticoid tapering was difficult, the introduction of upadacitinib resulted in remission of both atopic dermatitis and immunoglobulin G4-related disease without glucocorticoid dose escalation. Peripheral blood flow cytometry analysis showed that the proportions of activated non Th1/Th17 cells subset (Th2 cells), follicular helper T cells, and plasmocytes were increased before upadacitinib therapy but all normalised after treatment. Interleukin-4 and interleukin-21 signals are important for the differentiation of CD4+ T cells into type 2 helper T or B cells in the peripheral blood. Our case suggested that inhibition of Janus kinase 1, which mediates these signals, might have contributed to improved pathological conditions in immunoglobulin G4-related disease.

Immunoglobulin G4-related disease mimicking an appendiceal neoplasm: a case report.

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition characterized by chronic activation of the immune system and a tendency to form tumorous lesions. IgG4-RD is frequently characterized by the presence of tumor-like masses affecting multiple organs and is easily mistaken for a malignant neoplasm. However, IgG4-RD affecting the appendix is extremely rare, with only seven cases reported previously. We report the case of a woman in her early 60s who presented with insidious abdominal pain and radiological findings mimicking appendiceal neoplasms. After diagnosing appendiceal neoplasms, surgery was performed. The patient had a serum IgG4 concentration of <1.35 g/L, which did not satisfy one of the three revised comprehensive diagnostic criteria for IgG4-RD. A pathological examination was conducted, and the patient was diagnosed with appendiceal IgG4-RD. To the best of our knowledge, there have been no previously reported cases of IgG4-RD affecting the appendix in patients with low serum IgG4 concentrations. This report may prove beneficial for the future understanding of IgG4-RD and for the revision of diagnostic and treatment strategies.

Immunoglobulin G4-Related Disease Affecting the Tonsil: Case Report and Literature Review

Immunoglobulin G4-related disease (IgG4-RD) can involve multiple sites throughout the body. The most commonly affected sites in the head and neck are the salivary and lacrimal glands, respectively. Very few cases of IgG4-RD manifesting in the tonsils have been reported. Herein, we report the imaging findings of a 49-year-old female with pathologically confirmed IgG4-RD after a right-side tonsillectomy. The lesion showed diffuse homogeneous enhancement and appeared isointense and slightly hyperintense on T1- and T2-weighted magnetic resonance imaging, respectively. Diffusion restriction was also observed, which was considered to be due to the large number of IgG4-rich plasmacytes, and could vary depending on the degree of fibrosis. As distinguishing IgG4-RD from other diseases based solely on imaging is challenging, it is important to consider differential diagnosis, and clinical considerations are essential.

The "great imitator": IgG4-related disease of the oral cavity. Two case reports and scoping review.

This study aimed to review the lesser-known intraoral manifestations of immunoglobulin G4-related disease (IgG4-RD). In this paper we report an unprecedented case of oral IgG4-RD mimicking angiolymphoid hyperplasia with eosinophilia (ALHE), and another case presenting as plasma cell gingivitis. We then performed a scoping review of published cases of IgG4-RD involving the oral cavity. The following data were collected for each case: age, sex, intraoral site(s) involved, clinical appearance, imaging features, serum IgG4 values, histopathology, treatment, and follow-up duration. Fifty-one cases of oral IgG4-RD were published in literature. The hard palate and jaw bones were the two main locations reported, while the histological identification of a IgG4/IgG plasma cells ratio ≥40% was fundamental for diagnosis. Conversely, the pathological features of storiform fibrosis and obliterative phlebitis were not common. Future reports regarding oral IgG4-RD should report clear adherence to the recognized international diagnostic criteria of the disease.

Urinary bladder involvement in IgG4-related disease: A case-based review.

Immunoglobulin G4-related disease (IgG4-RD) is an immune-driven fibroinflammatory disease that presents as tumefactive lesions that not only commonly affects the pancreas, lacrimal and salivary glands, lung, liver and kidney but can also affect any organs. However, involvement of the urinary bladder in IgG4-RD is rarely reported. We describe a case of IgG4-RD involving the urinary bladder mimicking carcinoma and review the published literature-a 39-year-old male presented with complaints of dysuria, urgency and hesitancy. Ultrasound revealed a hyperechoic lesion protruding from the anterior of the urinary bladder wall with partial obstruction to bladder outflow, likely to be a pedunculated bladder mass with high suspicion for malignancy. A contrast-enhanced computed tomography abdomen showed a large irregular lobulated heterogeneously enhancing lesion involving the anteroinferior wall of the urinary bladder extending from mid-body up to the neck region with significant perivesical fat stranding and multiple ill-defined perivesical deposits along with hypodense soft tissue lesion in the perigastric region at the level of the body of the stomach. CT-guided perigastric and ultrasound-guided biopsy from the urinary bladder mass confirmed the diagnosis of IgG4-RD. The patient was treated with glucocorticoids. He is doing well after a 1-year follow-up without recurrence, and a repeat ultrasound showed a significant reduction in the size of the urinary bladder mass. The diagnosis of IgG4-RD should be considered in the differential diagnosis of a urinary bladder mass. High index of suspicion and prompt initiation of therapy are required to minimise residual damage and the need for surgical intervention.

Immunoglobulin G4-related Disease: A Series of Four Cases

Immunoglobulin G4-related Disease (IgG4-RD) is an immune-mediated fibroinflammatory disease that affects multiple organs, resulting in tumefactive lesions and/or organ dysfunction. This chronic, multiorgan inflammatory process is characterised by the infiltration of IgG4-positive plasma cells and has a variable clinical presentation depending on the organ involved. The present case series discusses four cases (two males and two females) of IgG4-RD involving different sites in patients presented to present Institution. The authors reviewed four cases of IgG4-RD, including clinical details, biochemical, radiological, and histopathological features. The case series includes IgG4-RD masquerading as meningioma, IgG4-related sclerosing cholangitis, IgG4-RD of the thyroid gland, and IgG4-RD of the lacrimal gland. Since IgG4-RD has non specific clinical features, histopathological analysis and immunohistochemistry play a pivotal role in diagnosis. Despite its diagnostic difficulties, earlier recognition is crucial to prevent significant morbidity and extensive fibrosis leading to organ failure.

The assessment of 18F-FDG PET/CT in IgG4-related disease: Case report and review of the literature

Immunoglobulin G4-related disease (IgG4-RD) is easily misdiagnosed. We report a case of IgG4-RD, whose main complaint was swollen eyelids, revealed by 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomography/computed tomography (PET/CT) and confirmed by pathological analysis from the submaxillary nodes. A 49-year-old woman complained about a bilateral swollen eyelid with blurred vision for 2 years. An enlarged submandibular lymph node was found during a physical examination. Head-enhanced magnetic resonance imaging (MRI) showed that the nasopharyngeal soft tissues were thickened, and the bilateral cervical lymph nodes were enlarged. A nasopharyngoscopy and tissue biopsy indicated chronic inflammation. 18F-FDG PET/CT was taken to eliminate malignant tumor metastasis, and the results suggest autoimmune disease. A biopsy of submandibular lymphatic nodes was taken, and the immunohistochemical staining showed IgG4-positive cells. Finally, IgG4-RD was diagnosed with elevated serum IgG4. The diagnosis of IgG4-RD is based on a comprehensive judgment of clinical symptoms, serum IgG4 levels, imaging studies, and pathological evidence. Ophthalmologists should be aware of the general conditions of patients who complain of unexplained ocular swelling, and 18F-FDG PEC/CT is strongly recommended. Compared with histopathologic examination, 18F-FDG PEC/CT can display changes in morphology and metabolism in involved organs and is noninvasive. It can be helpful in detecting, diagnosing, characterizing, and monitoring the response of the IgG4-RD.

IgG4-related diseases involving pleura: a case report and literature review

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibro-inflammatory disease with the potential to involve virtually all organs, including the pancreas, kidneys, lungs, and pleura, amongst others. IgG4-RD pleural involvement may cause diverse complications such as pleural effusion, pleural thickening, pleural nodules, and additional lesions, which can be presented in many clinical diseases. However, isolated cases of pleurisy are still rare in IgG4-RD. We report a 72-year-old patient who was admitted to our hospital with cough, expectoration, and fatigue. He had a right-sided pleural effusion, and the tissue evaluation of the pleural biopsy by medical thoracoscopy met the diagnostic criteria of IgG4-RD. His serum IgG4 levels were elevated and he was finally diagnosed with IgG4-RD pleural involvement. He was subsequently started on prednisone 40 mg daily and his pleural effusion was almost disappeared 2 weeks later. This paper reported a case of IgG4-RD who had exclusive involvement of the pleura and highlighted the significance of considering IgG4-RD as a potential diagnosis in patients with unexplained pleural effusion.

Analysis of the saliva microbiome in patients with immunoglobulin G4-related disease.

This article aims to investigate the saliva microbiome in patients with immunoglobulin G4-related disease (IgG4RD) compared with primary Sjögren's syndrome (SS). Saliva samples were collected from 11 IgG4RD and 11 SS patients who visited IMSUT Hospital, The Institute of Medical Science, The University of Tokyo. Deoxyribonucleic acid (DNA) was extracted from the samples, and primers were used to amplify the V3-V4 regions of bacterial and archaeal 16S ribosomal RNA (rRNA) genes, which was then analysed by paired-end sequencing. Amplicon reads were processed using QIIME2 to generate representative sequences. The Greengenes database was used to identify the bacterial flora in each sample and compare them between groups. The IgG4RD and SS groups exhibited differences in bacterial diversity. Cluster analyses of attributed classification groups by species and disease showed that IgG4RD and SS cases formed individual clusters. Significant differences in relative abundance between IgG4RD and SS were observed for the following organisms: Mogibacterium (P = .0051), Solobacterium moorei (P = .0195), Slackia (P = .0356), and Moryella (P = .0455). Salivary microbiome analysis of IgG4RD and SS patients revealed significantly higher relative proportions of Mogibacterium, S. moorei, Slackia, and Moryella bacteria in IgG4RD compared with SS.

Immunoglobulin G4-related disease mimicking lymphoma: Challenging to diagnose

Practically, all major organ systems can be impacted by an immune-mediated fibro-inflammatory condition known as immunoglobulin G4-related disease (IgG4-RD). Even though it is not unusual, the level of orbital involvement in IgG4-RD can change depending on where the lymphoplasmacytic infiltrate is located. We address a case of IgG4-RD in this study who presented with large bilateral upper and lower eyelids swelling, mediastinal lymphadenopathy, and elevated serum IgG4. It was necessary to do a histopathology examination to confirm the diagnosis of the IgG4-RD and rule out any possible mimicking hematological conditions. In conclusion, this case report emphasizes the value of clinical symptoms and imaging in reducing the number of potential diagnoses, although biopsy remains a gold standard to confirm the diagnosis of IgG4-RD.

Immunoglobulin G4-related disease diagnosed by prostate biopsy: a case report

BackgroundImmunoglobulin G4-related disease is characterized by swelling of various organs throughout the body and nodules/hypertrophic lesions. However, its cause remains unknown. We report a case of immunoglobulin G4-related disease that was diagnosed based on the histopathological findings of prostate biopsy.Case presentationA 72-year-old Japanese man had been treated by a nearby doctor for hypertension, but subsequently developed lower urinary tract symptoms and was prescribed an α1 blocker for 1 year. However, the patient was subsequently referred to our department because his symptoms did not improve. Prostate-specific antigen was 1.258 ng/ml; however, the nodule was palpable in the right lobe on digital rectal examination, and magnetic resonance imaging suggested Prostate Imaging and Reporting and Data System category 3. Therefore, transrectal prostate needle biopsy (12 locations) under ultrasound was performed. Histopathological examination revealed no malignant findings, although infiltration of lymphocytes and plasma cells, and partial fibrosis were observed. No remarkable findings of obstructive phlebitis were observed. Immunoglobulin G4-related disease was suspected, and immunoglobulin and immunoglobulin G4 immunostaining was performed. Immunoglobulin G4 positive plasma cells were observed in a wide range, immunoglobulin G4 positive cells were noted at > 10 per high-power field, and the immunoglobulin G4 positive/immunoglobulin G positive cell ratio was > 40%. Serum immunoglobulin G4 levels were high at 1600 mg/dl. Enhanced abdominal computed tomography findings suggested periaortitis. Additionally, multiple lymphadenopathies were observed around the abdominal aorta. The patient was accordingly diagnosed with immunoglobulin G4-related disease definite, diagnosis group (definite). We proposed steroid treatment for periaortic soft tissue lesions and lower urinary tract symptoms; however, the patient was refused treatment. A computed tomography scan 6 months after diagnosis revealed no changes in the soft tissue lesions around the aorta. Follow-up computed tomography examinations will be performed every 6 months.ConclusionIf immunoglobulin G4-related disease is suspected and a highly invasive examination is required for histopathological diagnosis, this can be performed by a relatively minimally invasive prostate biopsy for patients with lower urinary tract symptoms. Further evidence is needed to choose an optimal candidate for prostate biopsy for lower urinary tract symptoms patients with suspicion of immunoglobulin G4-related disease. For patients with lower urinary tract symptoms with immunoglobulin G4-related disease or a history, performing a prostate biopsy may avoid unnecessary treatment. However, if steroid therapy is ineffective, surgical treatment should be considered.

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.

Nationwide epidemiological survey of immunoglobulin G4-related disease with malignancy in Japan.

To clarify the clinicoepidemiological characteristics of immunoglobulin G4 (IgG4)-related disease (IgG4-RD) with malignancy, a nationwide epidemiological survey was conducted. Immunoglobulin G4-related disease patients with malignancy who had visited selected hospitals in Japan were surveyed. The study consisted of two stages: the number of IgG4-RD patients with malignancy was estimated by the first questionnaire and their clinicoepidemiological characteristics were assessed by the second questionnaire. The frequencies of autoimmune pancreatitis (AIP), IgG4-related sialadenitis, IgG4-related eye disease, IgG4-related kidney disease, and IgG4-related retroperitoneal fibrosis were 44.7%, 20.8%, 14.0%, 5.16%, and 5.12%, respectively. The overall prevalence of malignant disease in IgG4-RD cases was estimated to be 10900 per 100000 cases, which was significantly higher than that of malignant disease in the general population. The prevalence of malignant lymphoma in IgG4-RD cases was the highest and was estimated to be 1985 per 100000 cases. IgG4-related kidney disease had the highest frequency of malignant disease (17.1%). In data from 200 patients, 61 (30.5%) cases of cancer were found 2years or more before the IgG4-RD diagnosis, 92 cases (46%) during the 1year preceding or following IgG4-RD diagnosis, and 62 cases of cancer (31%) 2 or more years following IgG4-RD diagnosis. The nationwide survey for IgG4-RD with malignancy in Japan showed that IgG4-RD may be related with malignant diseases.

Immunoglobulin G4-related disease presenting with pulmonary manifestations, lymphadenopathy, and vocal cord immobility

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated state, which includes a group of disorders that can affect nearly any organ. Pulmonary involvement can present with nonspecific signs, symptoms, and highly variable radiological picture. Recognition of the disorder mainly relies on histopathological findings and immunohistochemical staining. Serum IgG4 levels also help in diagnosis. Glucocorticoids are the first choice for treatment. As this condition mimics many infective, inflammatory, and malignant disorders, a comprehensive diagnostic workup is required before reaching the diagnosis. We report a case of IgG4-RD with pulmonary manifestations, lymphadenopathy, and vocal cord immobility.

Mass-forming immunoglobulin G4-related disease shows indolent clinical course after surgical resection, clinicopathological analysis of a series of 15 cases.

The purpose of this study is to characterize the clinicopathological features of mass-forming immunoglobulin G4-related disease (IgG4-RD). A retrospective search for cases of mass-forming IgG4-RD diagnosed at Singapore General Hospital between 2008 and 2019 was performed. A total of 15 cases of mass-forming IgG4-RD were identified. The male-to-female ratio was 2.5:1, and the median age was 61years old. The majority of cases showed a solitary lesion (12/15) with a mean size of 35mm. IgG4-RD was considered as a clinical differential diagnosis only in one case (1/15) prior to the surgical resection. Diagnostic histopathological features, such as dense lymphoplasmacytic infiltrate positive for IgG4 plasma cells (15/15), storiform fibrosis (15/15), and obliterative phlebitis (9/15), were observed in most cases. These findings were distributed heterogeneously within the lesions. Cases with single organ involvement showed a low relapse rate (2/10) and normal serum IgG4 level after surgical resection. Mass-forming IgG4-RD has a male predilection and involves various organ systems. It may be initially misdiagnosed as malignancy and undergo surgical resection. The diagnostic histological features of IgG4-RD are readily identified in different organs. However, they may be distributed heterogeneously within a single lesion. Cases of single organ involvement show an indolent clinical course and normal serum IgG4 level after surgical resection.

AN UNUSUAL CASE OF STEROID-RESISTANT IGG4-RD AFFECTING THE MAXILLARY ALVEOLAR PROCESS

<h3>Introduction</h3> Immunoglobulin G4-related disease (IgG4-RD) is an autoimmune fibroinflammatory condition that is becoming increasingly recognized in the head and neck. I present a rare case of IgG4-RD originating in the alveolar process of the maxilla with orbital and maxillary sinus involvement that was unresponsive to traditional management. <h3>Case Presentation</h3> A 37-year-old Somalian woman presented with a 4-month history of progressive swelling of her right cheek and trismus. She had paresthesia and neuropathic pain affecting the V2 and V3 regions of the right trigeminal nerve. Testing of cranial nerve V revealed that she had decreased light-touch sensation over the site of swelling. Her hearing was reduced on the right side based on a whisper test. <h3>Investigations</h3> Ultrasound, magnetic resonance imaging, and computed tomography confirmed a mass centered on the right maxillary alveolus extending into the right buccal and masticator space, maxillary sinus, and orbit with involvement of the right infraorbital and greater palatine nerves. Histopathologic analysis revealed a storiform pattern of stromal fibrosis with a lymphoplasmacytic infiltrate and obliterative vasculitis. There was an increased number of IgG4⁺ plasma cells on immunostaining. <h3>Treatment</h3> She was started on corticosteroid but showed no response. Treatment with cyclophosphamide and rituximab provided improvement clinically and symptomatically. <h3>Discussion</h3> Clinically, IgG4-RD presents as a tumefactive, tissue-destructive lesion and often mimics malignant tumors, which can complicate diagnosis. IgG4-RD can be managed medically, and it is important to differentiate this disease from other pathologies in order to avoid invasive surgical management.

Azathioprine Monotherapy for the Cases of Immunoglobulin G4-Related Disease With Contraindications to Glucocorticoids.

Noda, Seiji MD; Honda, Suguru MD; Hirota, Yuka MD, PhD; Ito, Takashi MD, PhD; Hasegawa, Hisanori MD, PhD; Kimura, Naoki MD, PhD; Matsuo, Yusuke MD, PhD; Iwai, Hideyuki MD, PhD; Kohsaka, Hitoshi MD, PhD; Yasuda, Shinsuke MD, PhDAuthor Information

A renal unit saving approach to IgG4 related periureteral mass mimicking malignant ureteral tumor

Immunoglobulin G4-related disease (IgG4-RD) is a rare disease with few cases mimicking ureteral tumour identified after the ablative surgery. We report a case of IgG4-RD that presented as a ureteral mass which was diagnosed prior to surgery and managed conservatively. A 63-year-old man presented with prior diagnosis of the right ureteric tumour but a radiological review suspected it could be something else. The patient underwent laparoscopic biopsy from the periureteric mass. Biopsy reported to be IgG-4 disease and managed conservatively. This case highlights the rare possibility of IgG4-disease mimicking ureter tumour and if diagnosed prior to extirpative surgery can result in salvage of the kidney.

S2589 A New Great Mimicker: A Rare Case of IgG4-Disease With Isolated Sclerosing Cholangitis

INTRODUCTION: Immunoglobulin G4-related disease (IgG4-RD) is a rare newly discovered systemic immune-mediated fibroinflammatory disease of unknown etiology that can involve multiple organs. IgG4-RD has a broad spectrum of entities. IgG4-related sclerosing cholangitis is the biliary manifestation of IgG4-RD, typically occurring together with type 1 AIP, but isolated IgG4-SC accounts for only 8% of IgG4-RD cases. Although the mainstay of IgG4-SC treatment is steroid (with and /or without immunosuppressants), but clinical studies are still scarce about this disease. CASE DESCRIPTION/METHODS: We present a rare and challenging case of a 60-year-old male who presented with steatorrhea and elevated liver enzymes without clinical signs of obstructive jaundice. Imaging revealed mild intrahepatic biliary ductal dilatation and mild wall thickening with no evidence of pancreatitis or mass. Esophagogastroduodenoscopy (EGD) and small bowel biopsy were unremarkable for malabsorption disorders. ERCP and EUS-FNA were inconclusive but excluded malignancy. However, a high index of suspicion for IgG4 has driven to check serology and surprisingly it has revealed a strongly elevated IgG4 level. The patient was started on steroid and later immunomodulator with subsequent clinical and serological improvement as well as resolution of the biliary ductal dilatation on imaging afterward.We here report a unique case of isolated IgG4-related sclerosing cholangitis with uncommon presentation and in the absence of AIP, diagnosed by clinical correlation, serology, response to steroids, and exclusion of other possible disorders. DISCUSSION: IgG4-RD is a newly recognized disease in the early 2000s, with unknown exact prevalence. The disease is difficult to diagnose and still does not have its own unique International Statistical Classification of Diseases and Related Health Problems (ICD)-10 code. IgG4-RD can mimic other autoimmune rheumatic diseases such as Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), and granulomatosis with polyangiitis, as well as a number of other conditions. An isolated IgG4-SC may also mimic other conditions such as primary sclerosing cholangitis (PSC) and cholangiocarcinoma (CCA); therefore, physicians must carry a high index of suspicion for this under-recognized disease as IgG4-SC can respond to steroids in comparison to malignancy which is treated with surgical intervention. Early diagnosis and treatment are required to prevent irreversible fibrosis, biliary sepsis, and hepatic failure.Figure 1.: ERCP showing normal biliary tree with no focal lesions.