Perplexing lesions of the sinonasal cavity and skull base: IgG4-related and similar inflammatory diseases

Sinonasal immunoglobulin G4-related disease: a case report of an atypical and rare entity

BACKGROUND

Immunoglobulin G4-related disease is marked by extensive inflammation and fibrosis of an unknown autoimmune component, with an overall incidence ranging from 0.78 to 1.39 per 105 person-years. Sinonasal immunoglobulin G4-related disease is atypical and exceedingly uncommon in the existing literature, frequently manifesting clinically as chronic rhinosinusitis, epistaxis, and facial pain.

CASE PRESENTATION

This report describes a 25-year-old Iraqi female who has been suffering from symptoms of chronic rhinosinusitis for 8 years. Despite undergoing several surgeries, there has been no improvement in her symptoms. A tissue biopsy that revealed dense lymphoplasmocytosis with noticeable plasma cell infiltration, storiform fibrosis, and obliterative angitis, along with positive immunohistochemical staining for Immunoglobulin G4 plasma cells, finally confirmed the diagnosis of sinonasal immunoglobulin G4-related disease. The patient responded well to oral prednisolone and methotrexate treatments.

CONCLUSIONS

The main objective of the current report is to raise awareness among physicians about the significance of promptly identifying and diagnosing this rarity, thus preventing the adverse consequences linked to delayed diagnosis and treatment initiation.

Giant skull base mass need not be a tumor - a rare presentation of IgG4-related disease

BACKGROUND

Giant intracranial 'IgG4-related' lesions are uncommon. They may present as pachymeningitis or localized mass. Here we report, probably, the largest IgG4 skull base mass ever to be reported.

CASE

A 40-year male presented with headache, diplopia, right-sided sensori-neuronal hearing loss, and left spastic hemiparesis. Magnetic resonance imaging showed a lesion of 8.5 cm extending from the paranasal sinuses to the right petroclival region with uniform contrast enhancement and T2 hypointensity. Endonasal biopsy revealed respiratory epithelium with fibrosis, and lymphoplasmacytic infiltrate having IgG4 positive cells >30/HPF suggestive of 'IgG4-related' disease. Serum IgG4 was within normal levels. With oral prednisolone 60 mg given daily for 6 weeks and then tapered off over 8 weeks, he improved symptomatically.

CONCLUSION

Though rare, 'IgG4-related' disease can also present as a giant skull base mass and should be kept as a differential to fungal granulomas and meningiomas. As they improve dramatically with medical management, extensive skull base resection should not be planned before obtaining a tissue biopsy, especially when there is extension into paranasal sinuses and T2 hypointensity.

Autoimmune Pancreatitis Type 1 with Biliary, Nasal, Testicular, and Pulmonary Involvement: A Case Report and a Systematic Review

INTRODUCTION

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated condition associated with fibroinflammatory lesions that can occur at almost any anatomical site. It often presents as a multiorgan disease that may mimic malignancy, infection, or other immune-mediated conditions. Autoimmune pancreatitis (AIP) type 1 is the most prominent manifestation of IgG4-RD in the digestive tract, with common extra-pancreatic inflammation. We present the first patient with AIP and involvement of the testicles and nasal cavity.

PATIENT AND METHODS

A case of a patient with AIP type 1 and other organ involvement (bile ducts, testicles, nasal polyps, and lungs) is described. Additionally, a systematic review of AIP type 1 with testicular and nasal involvement was conducted.

RESULTS

The systematic review found two cases of AIP type 1 with testicular involvement and 143 cases with AIP type 1 with nasal cavity involvement. None of them had both testicular and nasal involvement.

CONCLUSIONS

This is the first case of AIP type 1 with other organ involvement, including testicular and nasal involvement, to be described. The number of patients with nasal and testicular involvement described in the literature is low. Creating awareness of this rare clinical condition is necessary, especially due to the very effective available treatment with corticosteroids and rituximab.

IgG4-Related Disease Involving the Paranasal Sinus Orbit: A Case Report

Immunoglobulin G4-related disease (IgG4-RD) is a rare and complicated clinical disease entity newly identified in recent years. It is a chronic inflammatory disease mediated by the immune system that can affect various organs throughout the body, such as the pancreas, salivary gland (submandibular gland, parotid gland, and sublingual gland), lacrimal gland, and thyroid gland. In rare cases, it involves sinuses and orbits. We describe a 44-year-old patient who was hospitalized with distension and pain in her right eye. The lesions included the nasal sinus and orbit. IgG4-RD was diagnosed after surgery and the patient was treated without complications. This case report helps to provide clinicians with additional information to assist in the diagnosis of the disease.

Sinonasal IgG4-related sclerosing disease: A rare entity and challenging diagnosis

Objectives

To describe the rare presentation, imaging and histological findings, and treatments in patients with IgG4-related disease (IgG4-RD) and diagnostic pitfalls and difficulties.

Methods

Cases of sinonasal IgG4-RD were retrieved, and clinicopathological features were reviewed.

Results

Seven cases of sinonasal IgG4-RD were identified over an 11-year period, including four males and three females, with an age range of 19-66 years (median 58 years). Patients presented with symptoms related to the mass effect of the lesions or the destructive nature of the disease including fullness, swelling, obstruction, and pain. Serum IgG and IgG4 levels, IgG/IgG4 ratios, storiform fibrosis, obliterative phlebitis, and plasma cell infiltration were seen in varying proportions. Bony erosion and tissue inflammation were present in some cases.

Conclusion

Sinonasal IgG4-RD is exceedingly rare among other IgG4-RD and varied in its clinical presentation thus posing as a clinically difficult disease to diagnosis. Proper clinical, pathological, and immunohistopathological analysis is required for accurate diagnosis. Such disease should be considered in all cases of similar presentation to those in this study.Level of Evidence: 4.

IgG4-Related Sclerosing Disease of the Temporal Bone: A Systematic Review

OBJECTIVE

IgG4-related disease (IgG4-RD) involving the temporal bone is an uncommon and underrecognized pathology often mistaken for malignancy. This systematic review is the first that aims to thoroughly analyze IgG4-RD of the temporal bone.

DATABASES REVIEWED

Ovid MEDLINE, EMBASE, Cochrane Library, and Google Scholar.

METHODS

We used the following search keywords: "lgG4-RD," "skull," "skull base," "cranial," "temporal bone," "inner ear." We additionally manually searched the bibliographies of relevant articles. The JBI Critical Appraisal Checklist for Case Reports and Case Series was used to assess the risk of bias; because of the scarcity of the reports, data were available through limited case series and reports; thus, data synthesis was not possible.

RESULTS

We identified 17 studies with 22 cases with temporal bone involvement. The most common presenting symptoms were hearing loss, otalgia, and headache. The mastoid and petrous bone were the most affected anatomical areas. Both computed tomography and magnetic resonance imaging were used. Biopsies showed the characteristic lymphoplasmacytic infiltrate in all cases, with histopathology being the diagnostic modality that set the diagnosis. Most patients were treated with corticosteroids ± surgery or a combination of corticosteroids and immunosuppressants with 95.5% symptomatic response and disease control.

CONCLUSION

IgG4-RD of the temporal bone radiologically manifests as space-occupying, lytic lesions; clinically, it presents with vague otological symptoms. Diagnosis involves a thorough workup, with histopathology being crucial in setting a definite diagnosis. IgG4-RD tends to respond well to systemic corticosteroids, whereas surgery is mostly required for diagnostic purposes.

Case Report: Diagnosis of Petrous Apex IgG4-Related Disease by Middle Cranial Fossa Craniotomy and Temporal Bone Biopsy

Introduction

Primary IgG4-related disease (IgG4-RD) of the temporal bone is a rare condition. Unlike typical petrous apicitis or Gradenigo syndrome, our patient presented exclusively with unilateral cranial nerve VI palsy and symptoms of diplopia. Skull base imaging demonstrated a destructive bony lesion in the petrous apex. Imaging and systemic investigations were insufficient to support a diagnosis. The diagnosis was achieved histologically after acquiring the specimen by middle cranial fossa craniotomy and temporal bone biopsy. This case report is thought to be the first published description of a diagnosis of IgG4-RD proven with the middle cranial fossa approach.

Case Report

We describe a 29-year-old female with primary IgG4-RD of the petrous apex of the temporal bone. This patient presented with a few-month history of left-sided headache and recent-onset diplopia due to paralysis of cranial nerve VI. Imaging demonstrated a petrous apex lesion, and comprehensive systemic investigations could not reach a diagnosis. A middle cranial fossa craniotomy and a biopsy of the temporal bone lesion were undertaken to establish the diagnosis. Histological confirmation of IgG4-RD was proven. Following treatment with corticosteroids, the patient experienced complete recovery and resolution of her symptoms.

Conclusion

This study describes a case of primary IgG4-RD of the petrous apex of the temporal bone that presented with diplopia and was diagnosed by middle fossa craniotomy and temporal bone biopsy. To the best of our knowledge, this is the first case description where primary diagnosis was made based on middle cranial fossa craniotomy and temporal bone biopsy.

Nasolacrimal Duct Malignancy or IgG4- Related Disease? A Curious Case Report of a Nasal Vestibular Mass and Review of the Literature

IgG4-related disease (IgG4-RD) is a fibro-inflammatory condition associated with tumefactive lesions at multiple sites. IgG4-RD was initially recognized in 2001 in a case of autoimmune pancreatitis. However, the disease was not limited to the pancreas but involved other organs such as the bile ducts, lacrimal glands, lymph nodes and salivary glands. IgG4-RD is rarely seen with an estimated incidence of 0.2 to 1/100.000 as reported in Japan, but with minimal to no incidence data have been published in Western countries. We hereby report a case of an IgG4-related mass arising from the nasolacrimal duct, masquerading as a sinonasal mass.

Atypical IgG4-related disease limited to the sino-nasal cavity: A case report

Given the overlapping clinical features of sino-nasal immunoglobulin 4-related disease (IgG4-RD) to rhinitis or rhinosinusitis, this paper aims to delineate this rare, isolated manifestation significant to physicians for their daily practice and researchers contributing to this field.

IgG4-Related Disease of the Skull and Skull Base-A Systematic Review and Report of Two Cases

OBJECTIVE

IgG4-related disease (IgG4-RD) is an inflammatory process that uncommonly can present in the skull base and calvarium and mimic a tumor but the nature of this condition is not well summarized in the neurosurgical literature.

METHODS

A review was performed of 2 cases of IgG4-RD in the skull base highlighting the diagnostic challenges with assessment of these skull base lesions, and a systematic review of relevant literature was carried out.

RESULTS

A systematic review of the literature conducted in accordance with PRISMA guidelines identified 113 articles, with 184 cases of IgG4-RD in the skull base or calvarium. The most commonly affected locations include the meninges, cavernous sinus, base of the posterior fossa, clivus, and mastoid bone. Headache, visual and auditory disturbances, cranial nerve dysfunction, and seizures were the most common presenting symptoms. Medical treatment was highly successful and most commonly consisted of corticosteroids coadministered with immunosuppressive agents such as rituximab. Prevalence seemed to be equal between sexes, and serum IgG4 levels were increased in 61% of patients. Delayed diagnosis and a need for multiple biopsies were reported in numerous cases. Two cases of skull base IgG4-RD from the authors' institution show the variable presentations of this disease. More invasive surgical biopsies were required in both cases, and corticosteroid treatment led to significant clinical improvement.

CONCLUSIONS

IgG4-RD is an uncommon condition with an increasing body of reported cases that can affect the skull base and calvarium and should be in the differential diagnosis, because delay in diagnosis and treatment may be common.

Sinonasal IgG4-related disease: a rare and emerging entity broadening the differential diagnosis in the sinonasal universe

BACKGROUND

IgG4-related disease (IgG4-RD) is a multi-organ immune-mediated disorder characterized by fibroinflammatory mass-forming lesions, mimicking malignancy or infection. While well-documented in salivary glands, orbit and thyroid in the head and neck, sinonasal IgG4-RD is rare.

METHODS

Cases of sinonasal IgG4-RD were retrieved, and clinicopathological features reviewed.

RESULTS

Seven cases of sinonasal IgG4-RD were identified over a 2-year period, including three males and four females, with an age range of 13-48 years (median: 32 years). Patients presented with cheek swelling, pain and visual disturbances. Serum IgG4 levels were mildly elevated. Storiform fibrosis, obliterative phlebitis and plasma cell infiltration were seen in varying proportions. Destruction of bone and subepithelial mucoserous glands was present. ALK-1 negativity distinguished from inflammatory myofibroblastic tumor.

CONCLUSION

Sinonasal IgG4-RD expands the growing spectrum of IgG4-RD. A high degree of suspicion is required to include IgG4-RD in differential diagnosis of sinonasal masses, and perform detailed histological and immunohistochemical workup for accurate diagnosis.

IgG4-Related Disease of Skull Base: Case Series of 3 Patients with Headache

BACKGROUND

IgG4-related disease (IgG4-RD) is an immune-mediated, systemic, fibroinflammatory disease. IgG4-RD may manifest in almost every part of the human body. Here, we describe 3 patients with a skull base manifestation of IgG4-RD that mimicked malignancy.

CASE DESCRIPTION

Patient 1, a 73-year-old male, presented with a mass in the left nasopharynx and clivus. Patient 2, a 73-year-old male, presented with a mass in the left petrous bone and clivus with involvement of the left jaw joint. Patient 3, a 50-year-old male, presented with a lytic lesion of the clivus and sphenoid bone. All patients complained of headache and hearing loss. Serum IgG4 was normal, and imaging did not show systemic manifestation. Histology established the diagnosis of IgG4-RD. Two patients were treated successfully with prednisolone, hydroxychloroquine, and radiotherapy. One patient is monitored without treatment.

CONCLUSIONS

The described cases emphasize the broad clinical spectrum of IgG4-RD. The diagnostic workup may be challenging, and serum IgG4 may be normal, as demonstrated in these cases. Careful histopathologic examination of the tissues remains essential. Timely diagnosis of IgG4-RD is important to prevent secondary organ damage in patients with active disease.

Clinical significance of IgG4 in sinonasal and skull base inflammatory pseudotumor

INTRODUCTION

Inflammatory pseudotumor (IPT) in the sinonasal cavity and skull base region is benign non-neoplastic inflammatory process. However, IPT can mimic malignant tumor or infectious disease and there are difficulties in confirmation of diagnosis. The aim of study is to evaluate the clinical significance of immunoglobulin G4 (IgG4) in IPT in terms of steroid response and differential diagnosis with other skull base infiltrative lesions.

METHODS

Medical records were reviewed retrospectively from 1998 to 2016. Subjects diagnosed with IPT by surgical biopsy were enrolled. IgG4 positivity was defined as IgG4/IgG ratio > 0.4. Additionally, IgG4/IgG ratio was calculated in eight skull base osteomyelitis (SBO) patients.

RESULTS

Twenty-six IPT patients were included and the average age was 52.3 years, and 57.7% were male and 42.3% were female. Most lesions were involved in the sinuses (88.5%) and the incidence of extension beyond the sinuses itself was as follows: the cheek/hard palate/parapharynx (15.4%), orbit (61.5%), skull base (57.7%), and dura or brain (23.1%). All IPT cases revealed IgG4 + plasma cells and IgG4/IgG ratio over 0.4 was detected in 42.3% (11/26) of cases. In case of SBO, no patients had IgG4/IgG ratio exceed 0.4. Main treatment modality was systemic steroids (61.5%) and other modalities were used: surgery (3.8%), immunosuppressant (7.7%), radiotherapy (30.8%), or a combination of these modalities (15.4%). Steroid responses were not significantly different, but IgG4-positive group tended to have better response to steroid therapy.

CONCLUSIONS

IgG4-positive and IgG4-negative IPT patients revealed no differences in involvement sites, clinical course, and steroid responses. However, IgG4/IgG ratio and IgG4 + plasma cell count can provide a diagnostic clue for infiltrative skull base lesions such as IPT and a differential diagnosis of SBO.

The Clinicopathologic Spectrum of IgG4-Related Disease

Immunoglobulin G4-related disease is a fibroinflammatory systemic disease that is characterized by focal or diffuse organ infiltration by immunoglobulin G4-bearing plasma cells. Immunoglobulin G4-related disease may affect any organ, and a high index of suspicion is necessary for early detection to avoid irreversible fibrosis, organ dysfunction, and death. Tumor-forming lesions are common radiological features of immunoglobulin G4-related disease that need to be differentiated from malignancies. The diagnostic approach requires the integration of clinical, biochemical, and radiographic manifestations with classic histopathologic features, which remain crucial to diagnosis. The histology of immunoglobulin G4-related disease is determined by a dense lymphoplasmacytic infiltrate, storiform fibrosis, and obliterative phlebitis in the presence of increased immunoglobulin G4-positve plasma cells. Although immunoglobulin G4-related disease forms a distinct, clinically independent disease category, many questions and problems remain unanswered, especially on its pathogenesis and the role of immunoglobulin G4. Advances in the understanding of immunoglobulin G4-related disease are likely to change the diagnostic approach in the future and create potential targets for therapeutic purposes. Here we describe the concept of immunoglobulin G4-related disease and the most recent knowledge in the clinico-pathological characteristics on this emerging disease. This study can guide clinicians in early diagnosis and prevent unnecessary surgical resections.

Erdheim-Chester Disease: The Importance of Information Integration

Background

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis disorder that utilizes the RAS-RAF-MEK-ERK pathway. It has a highly variable clinical presentation, where virtually any organ can be involved, thus having the potential of posing a great diagnostic challenge. Over half of the reported cases have the BRAF V600E mutation and have shown a remarkable response to vemurafenib.

Case Presentation

We describe herein a patient with a history of stroke-like symptoms and retroperitoneal fibrosis that on initial pathology raised the possibility of IgG4-related disease. However, the patient was refractory to high-dose steroids and progressed further, developing an epicardial soft tissue mass and recurrent neurological symptoms. Integration of the above findings with new information at another hospital about a radiological history of symmetrical lower extremities long bone lesions raised the differential diagnosis of ECD. Molecular analysis of formalin-fixed paraffin-embedded tissue of both of the patient's retroperitoneal biopsies (the second one of which had shown a small focus of foamy histiocytes, CD68+/CD1a–) was positive for BRAF mutation, confirming the diagnosis of ECD. The patient demonstrated a dramatic and sustained metabolic response to vemurafenib on follow-up positron emission tomography scans.

Conclusion

This case highlights the need for developing a high index of suspicion for presentations of retroperitoneal fibrosis that could represent IgG4-related disease but fail to respond to steroids. When unusual multisystem involvement occurs, one should consider a diagnosis of a rare histiocytosis. Vemurafenib appears to be an effective treatment for even advanced cases of both ECD and Langerhans histiocytosis bearing the BRAF V600E mutation.

Imaging of IgG4-related disease of the head and neck

IgG4-related disease is a systemic, inflammatory disorder typically involving multiple organ systems. Several eponymous conditions described previously in the clinical and radiology literature are now recognised to be part of the IgG4-related disease spectrum. This includes multiple manifestations in the head and neck region, which are the subject of this review. Imaging can occasionally suggest the specific diagnosis of IgG4 disease. More commonly, it will be included in a limited differential diagnosis that requires clarification with the aid of image-guided biopsy. There are strict histopathological criteria for the diagnosis of IgG4-related disease.

IgG4-related disease causing facial nerve and optic nerve palsies: Case report and literature review

IgG4-related disease (IgG4-RD) is increasingly being recognized as an entity effecting the head and neck region. Although most commonly seen with salivary gland or paranasal sinus involvement, IgG4-RD may also involve the temporal bone and skull base. We report a rare care of a 61-year-old female with IgG4-RD presenting as synchronous lesions of the middle ear and middle cranial fossa with polyneuropathy of cranial nerves II, VI, and VII. Initial histopathological evaluation of her resected ear mass suggested a benign inflammatory process but no specific diagnosis. Her symptoms progressed over 10months prompting re-evaluation of the specimen and consideration of the IgG4-RD diagnosis. Key pathologic features included prominent lymphoplasmacytic population, storiform fibrosis, obliterative phlebitis, and IgG4 specific staining. The patient was treated with high-dose intravenous and oral steroids but was transitioned to azathioprine secondary to steroid-induced myopathy. Radiographic studies before and after treatment reveal marked improvement of the intracranial and extracranial disease. Correspondingly, her cranial neuropathies resolved. A high degree of clinical suspicion is necessary to diagnosis IgG4-RD. The diagnosis can be supported by elevated serum IgG, elevated IgG index, and pathognomonic histopathological findings. Primary treatment is with corticosteroids. However, immunotherapy using azathioprine or rituximab can be utilized in recurrent disease or patients with steroid intolerance.

Immunoglobulin G4-related sclerosing disease of the paranasal sinuses: A case report and literature review

Objective:

Immunoglobulin G4 (IgG4) related sclerosing disease (RSD) of the paranasal sinuses is a rare lesion of dense lymphoplasmacytic tissue, with a high proportion of IgG4+ plasma cells. We presented a rare case of IgG4-RSD with isolated involvement of the paranasal sinuses in the absence of multiorgan involvement.

Methods:

A case report and comprehensive literature review.

Results:

To our knowledge, only 11 cases of IgG4-RSD with paranasal sinus involvement have been reported. Patients with IgG4-RSD commonly present with epistaxis and symptoms that mimic chronic rhinosinusitis, e.g., rhinorrhea, nasal obstruction, and facial pressure. On imaging, an expansive and erosive process is described. Surgery provides tissue for immunohistologic evaluation; however, there is a paucity of evidence about the direct extent of surgical resection or medical therapies. Postoperative steroids were typically started, although the regimen was not standardized.

Conclusion:

Few cases of paranasal sinus IgG4-RSD have been reported in the literature. Evidence-based recommendations regarding treatment and surveillance of paranasal sinus IgG4-RSD are lacking; however, most reports describe systemic steroids as the mainstay of treatment. This single subject analysis, with a review of previously reported cases adds to the expanding body of data related to this rare disorder.

IgG4-related disease presenting with destructive sinonasal lesion mimicking malignancy

IgG4-related disease is a newly recognized systemic fibroinflammatory disorder. We report a 36-year-old man who presented with intractable right nasal pain and frontal headache for 1 month. Computed tomography revealed an ill-defined lesion with bony erosion over the right anterior ethmoid sinus and middle turbinate. The lesion was resected through endoscopic anterior ethmoidectomy and middle turbinectomy. IgG4-related disease was definitively diagnosed according to histopathological features. Prednisolone was administered postoperatively. IgG4-related disease presenting with destructive sinonasal lesion mimicking malignancy is rare. Awareness is essential to avoid delayed diagnosis or unnecessary invasive intervention, because the disorder responds to glucocorticoid and immunosuppressant therapy.

A rare and emerging entity: Sinonasal IgG4-related sclerosing disease

BACKGROUND

Immunoglobulin G4 (IgG4) related sclerosing disease (rSD) is a new disease entity, first described in 2001, that involves autoimmune pancreatitis. Considered a systemic disease with lesions described in multiple organ systems, IgG4-rSD that affects the sinonasal region is rare. Our goal was to highlight the sinonasal presentation of this unique disease and to review previously reported adult cases from 2003 to 2014.

METHODS

Case report (a 72-year-old man who presented with left exophthalmos, periorbital pain, and epiphora) and review of the literature.

RESULTS

Radiographic workup with computed tomography and magnetic resonance imaging demonstrated a left sinonasal mass that involved the left maxillary and ethmoid sinuses, with surrounding bony destruction and orbital invasion. Nasal endoscopy demonstrated a fibrous lesion emanating in the middle meatus, with surrounding mucosal inflammation. The patient underwent an endoscopic biopsy, medial maxillectomy, and ethmoidectomy with tumor debulking. Pathology demonstrated inflamed respiratory mucosa with dense lymphoplasmacytic infiltrate and fibrosis; flow cytometry demonstrated no malignant cell populations; immunophenotyping demonstrated multiple foci of IgG4 cells. Plasma IgG4 was elevated in the setting of normal total IgG. The patient was treated with postoperative systemic and topical corticosteroids. Surveillance imaging studies and nasal endoscopy demonstrated disease resolution without recurrence.

CONCLUSIONS

Sinonasal IgG4-rSD is a rare disease that can present with bony and soft-tissue invasion. This was an exceptional case, with osseous involvement and orbital invasion. Immunohistologic workup is essential for diagnosis. It is important to differentiate this disease from sinonasal tumors. Treatment includes corticosteroids and surgical debulking. Sinonasal IgG4-rSD represents an emerging disease that may present challenges for future rhinologists.

Probable Immunoglobulin Subtype-G4-Related Disease in the Head and Neck from Foreign Body Injection: A Case Report

Introduction Immunoglobulin subtype G4-related disease (IgG4-RD) is a fibroinflammatory disease of unknown etiology, with manifestations involving nearly every organ system. Its association with foreign bodies is not established. Here, we present a novel case of IgG4-RD in response to foreign body injection.

Case Description A 58-year-old woman presented with history of persistent left facial pain, xerophthalmia, blurred vision, and trismus. The patient's medical history was significant for left-sided temporomandibular joint (TMJ) reconstruction with silicone injection into the joint. Magnetic resonance imaging revealed a lesion in the left skull base. Biopsies demonstrated the cardinal histopathological features of IgG4-RD. The patient was treated with a tapering dose of prednisolone followed by rituximab, resulting in tumor shrinkage and resolution of her symptoms.

Discussion This is the first reported case of IgG4-RD potentially precipitated by a foreign body, in this case injected silicone into the TMJ. The pathogenesis and etiology of IgG4-RD is still not fully elucidated, but allergic and reactive inflammatory reactions have been implicated in the disease process. This case report should raise the idea of reactive foreign bodies as a causative agent for IgG4-RD.