Clinical and pathological differences between Mikulicz's disease and Sjögren's syndrome

Mikulicz's disease combined with IgG4-related hypophysitis: a case report

BACKGROUND

IgG4-related diseases are very uncommon, and its diagnosis and treatment are complicated as it encompasses multiple disciplines.

CASE PRESENTATION

A 77-year-old woman was admitted with a jaw mass and nausea and vomiting. Laboratory tests showed elevated serum IgG4, pituitary MRI suggested thickening of the pituitary stalk, and head and neck CT suggested orbital and mandibular masses. Patients with mandibular mass were diagnosed with Mikulicz's disease with IgG4-related hypophysitis. We found no other evidence of causing thickening of the pituitary stalk. She was given oral prednisolone 30 mg daily, and her nausea and vomiting improved significantly, and the mandibular and ocular masses decreased in size.

CONCLUSION

Mikulicz's disease combined with IgG4-related hypophysitis is a rare case of IgG4-RD in elderly women. IgG4-RD is one of the causes of head and neck exocrine gland mass and pituitary stalk thickening in the elderly.

IgG4-related disease: an update on pathology and diagnostic criteria with a focus on salivary gland manifestations

Immunoglobulin G4-related disease (IgG4-RD) is a multi-organ disorder characterized by a highly variable clinical presentation depending on the affected organ/s, extent of tumefactive fibroinflammatory lesions, and associated functional impairment. The disease pursues a chronic, relapsing, often asymptomatic course and hence may pose a significant diagnostic challenge. Diagnostic delay can lead to progressive fibrosis and irreversible organ damage resulting into significant morbidity and even mortality. Given its broad clinical spectrum, physicians of all specialties may be the first clinicians facing this diagnostic challenge. Outside the pancreatobiliary system, the head and neck represents the major site of IgG4-RD with variable organ-specific diffuse or mass-forming lesions. In up to 75% of cases, elevated serum IgG4 levels are observed, but this figure possibly underestimates the fraction of seronegative cases, as the disease manifestations may present metachronously with significant intervals. Together with negative serology, this can lead to misdiagnosis of seronegative cases. A standardized nomenclature and diagnostic criteria for IgG4-RD were established in 2012 and revised in 2020 facilitating scientific research and expanding the range of diseases associated with IgG4 abnormalities. In addition to orbital pseudotumor, dacryoadenitis, Riedel thyroiditis, sinonasal manifestations, and rare miscellaneous conditions, IgG4-related sialadenitis is one of the most frequent presentations in the head and neck region. However, controversy still exists regarding the relationship between sialadenitis and IgG4-RD. This review focuses on the clinicopathological features of IgG4-related sialadenitis and its contemporary diagnostic criteria.

Bilateral swelling of the salivary glands and sicca symptoms: an unusual differential diagnosis-Kimura's disease, a rare allergic condition with a high IgE serum level-a case report and review of the literature

A 68-year-old woman presented with bilateral swelling of the salivary glands, sicca symptoms of eyes and mouth, itching, fatigue and weight gain of about 5 kg in the last 2-3 years. As part of a careful diagnostic work up including lab tests for antinuclear antibodies (ANA), antibodies to extractable nuclear antigens (ENA), anti-neutrophilic cytoplasmatic antiobodies (ANCA), immunoglobulin (Ig)G4, a whole body computed tomography (CT) and a parotid biopsy several rheumatic diseases such as Sjoegren's syndrome, IgG4-related disease and sarcoidosis were ruled out and, considering a very high titre of IgE, Kimura's disease was diagnosed. The case and a short review of the literature are presented.

Differentiation between IgG4-related Mikulicz disease and Sjögren's syndrome: A review case report and literature review

RATIONALE

IgG4-related diseases cause lesions in various organs throughout the body. In otorhinolaryngology, IgG4-related Mikulicz's disease is suspected and diagnosed based on the presence of lesions of the head and neck, salivary and lacrimal gland enlargement, and bilateral sinus opacity concentrated on the maxillary sinuses. However, in some cases, it is necessary to consider about differentiation between IgG4-related Mikulicz's disease and Sjögren syndrome.

PATIENT CONCERNS AND DIAGNOSIS

A 75-years-old male patient visited our hospital with bilateral otitis media with effusion, which was resistant to conservative treatment. Other symptoms at presentation included enlarged bilateral submandibular and sublingual glands marked oral dryness, severe decrease in saliva secretion (1 mL/10 minutes), and dry eyes. We conducted a Schirmer's and fluorescent dye tests, both of which were positive. High serum IgG4 levels were observed, and although the Sjögren syndrome (SS)-A/SS-B antibodies were negative, marked hypolacrimation and tear secretion were observed. Therefore, a detailed examination considering both IgG4-related Mikulicz's disease and SS was conducted. Salivary gland scintigraphy performed prior to the salivary gland biopsy revealed a marked decrease in uptake, which satisfied the diagnostic criteria for SS; however, it was difficult to diagnose IgG4-related disease based on the diagnostic definition.

INTERVENSIONS

Although a definitive diagnosis of SS was made, the persistent otitis media with effusion that was resistant to conservative treatment and bilateral mixed hearing loss were confirmed. As mixed hearing loss is considered an otological symptom of IgG4-related disease, oral steroid treatment was administered.

OUTCOME

Thereafter, marked recovery of hearing and reduced swelling and induration of the bilateral parotid and submandibular glands were observed. Clinically, IgG4-related Mikulicz's disease was strongly suspected, but a definite diagnosis of SS was made.

LESSONS

In the absence of an IgG4-related Mikulicz's disease diagnosis, careful differentiation between IgG4-related Mikulicz's disease and 2 diseases and their diagnostic criteria was essential.

T Cell Roles and Activity in Chronic Sclerosing Sialadenitis as IgG4-Related Disease: Current Concepts in Immunopathogenesis

IgG4-related disease is a multiorgan immunological fibroinflammatory disorder characterized by lymphoplasmacytic infiltration and fibrosis in multiple organs accompanied by high serum IgG4 levels. The salivary glands are the most common organs involved in this disease. Recently, chronic sclerosing sialadenitis affecting salivary glands, formerly known as Küttner's tumor, and Mikulicz's disease have been classified as a class of IgG4-related diseases. The etiopathobiology of IgG4-related disease is not fully understood. It has recently been hypothesized that the inflammatory and fibrotic process and the increased serum IgG4⁺ levels in IgG4-related disease are the result of an interaction between B cells and T helper cells, suggesting that T cells may play a key role in the pathogenesis of this disease. The aim of this review is to discuss the proposed roles of different T cell subsets in the pathogenesis of IgG4-related disease focusing on their roles in immunopathogenesis of IgG4-related sialadenitis.

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

BACKGROUND AND AIM

To clarify the clinicoepidemiological characteristics of immunoglobulin G4 (IgG4)-related disease (IgG4-RD) with malignancy, a nationwide epidemiological survey was conducted.

METHODS

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.

RESULTS

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 10 900 per 100 000 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 100 000 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 2 years or more before the IgG4-RD diagnosis, 92 cases (46%) during the 1 year preceding or following IgG4-RD diagnosis, and 62 cases of cancer (31%) 2 or more years following IgG4-RD diagnosis.

CONCLUSIONS

The nationwide survey for IgG4-RD with malignancy in Japan showed that IgG4-RD may be related with malignant diseases.

Immunoglobulin G4-related Disease: A New Systemic Disease Emerging in Japan

Immunoglobulin G4-related disease (IgG4-RD) is a fibro-inflammatory disease characterized by organ enlargement and elevated serum IgG4 levels. In 2003, IgG4-RD was proposed as a distinct form of IgG4-related systemic disease based on a histopathological study involving patients with autoimmune pancreatitis. IgG4-RD occurs mainly in older men and can affect almost any organ simultaneously or metachronously. Pathophysiologically, IgG4-RD occurs when an autoantigen triggers an immune response characterized by Th2 predominance with increased production of cytokines, such as interleukin 4 (IL-4), IL-5, IL-10, IL-13, and tumor growth factor-β (TGF-β), in the affected organ. IL-10 and TGF-β produced by the increased number of regulatory T cells induce a switch from B cells to IgG4-producing plasma cells and fibrosis, respectively. The characteristic histological features consist of dense infiltration of lymphocytes and IgG4-positive plasma cells, storiform fibrosis, and obliterative phlebitis. IgG4-RD is diagnosed based on a combination of clinical, serological, radiological, and histopathological findings. Differentiating IgG4-RD from malignant tumors or similar inflammatory diseases in the affected organs is important. The 2019 America College of Rheumatology/European League against Rheumatism classification criteria for IgG4-RD have high diagnostic sensitivity and specificity. IgG4-RD generally responds well to treatment with steroids, and a swift response is reassuring and provides further diagnostic confirmation. However, relapses are common during tapering or after cessation of steroids. In Japan, low-dose steroid maintenance therapy is usually given to prevent a relapse. B-cell depletion with rituximab is effective in patients resistant to or dependent on steroids. Most patients with IgG4-RD who receive steroid therapy show good short-term clinical, morphological, and functional outcomes. However, long-term outcomes, such as relapse, fibrosis development, and associated malignancies, have not been clearly defined. Therefore, novel treatment strategies, including rituximab, need to be tested in international randomized controlled clinical trials.

Amendment of the Japanese consensus guidelines for autoimmune pancreatitis, 2020

In response to the latest knowledge and the amendment of the Japanese diagnostic criteria for autoimmune pancreatitis (AIP) in 2018, the Japanese consensus guidelines for managing AIP in 2013 were required to be revised. Three committees [the professional committee for developing clinical questions (CQs) and statements by Japanese specialists; the expert panelist committee for rating statements by the modified Delphi method; and the evaluating committee of moderators] were organized. Twenty specialists in AIP extracted the specific clinical statements from a total of 5218 articles (1963-2019) from a search in PubMed and the Cochrane Library. The professional committee made 14, 9, 5, and 11 CQs and statements for the current concept and diagnosis, extra-pancreatic lesions, differential diagnosis, and treatment, respectively. The expert panelists regarded the statements as valid after a two-round modified Delphi approach with individually rating these clinical statements, in which a clinical statement receiving a median score greater than 7 on a 9-point scale from the panel was regarded as valid. After evaluation by the moderators, the amendment of the Japanese consensus guidelines for AIP has been proposed in 2020.

Non-infectious Dacryoadenitis

Dacryoadenitis is an inflammation of the lacrimal gland that may have various etiologies with similar presentations. Despite more recent elucidation of specific causes, the management has remained largely unchanged. Hence, the condition remains under biopsied with the rationale that empirical treatment with corticosteroids is effective for many of the causes. Dacryoadenitis, however, dacryoadenitis can be the presenting sign of an undiagnosed systemic disease and a mimick for lymphoma; hence, tissue diagnosis and systemic investigations play a vital role. A significant proportion of dacryoadenitis has a specific etiology, and IgG4-related dacryoadenitis is more frequently identified as a cause. We summarize the different types of immune-mediated dacryoadenitis, their clinical findings, histopathology, management, and prognosis. We have also highlighted and formulated practice guidelines for diagnosis and effective treatment based on the underlying systemic disease.

Thoracic paravertebral involvement in patients with IgG4-related disease: CT and MR imaging findings

OBJECTIVES

To retrospectively evaluate CT and magnetic resonance (MR) imaging thoracic paravertebral findings at baseline and follow-up in patients with IgG4-related disease.

METHODS

The study consisted of 36 patients with IgG4-related disease involving thoracic paravertebral regions (32 men and four women; mean age, 58 years; range, 25-78 years). A total of 36 patients underwent CT or MR imaging at baseline; 20 patients underwent follow-up. CT and MR images were reviewed and analysed in consensus by two radiologists for the various features of thoracic paravertebral lesions.

RESULTS

All lesions were located around two or more thoracic vertebrae, particularly the lower thoracic vertebrae (n = 36). The right side of vertebrae was predominantly affected in all cases (n = 36). Radiologically, IgG4-related thoracic paravertebral lesions were categorized into three types: solitary or multiple saddle-like masses type (32 patients); multiple nodules type (three patients); and invasively irregular mass type (three patients). All the types showed soft-tissue density on CT images, isointense on T1- and T2-weighted images, and homogeneous enhancement with penetration of small arteries in the lesions on contrast-enhanced CT and MR images. Steroid therapy administered to 20 patients dramatically diminished the mean maximum thickness in 18 patients. One patient with T7-12 vertebrae involved improved after steroid therapy.

CONCLUSION

IgG4-related paravertebral lesions occur mainly around the right side of the lower thoracic vertebrae and manifest as three major patterns of CT and MR imaging findings. Recognition of these diagnostic features will assist in the diagnosis and treatment of IgG4-related disease.

Clinical features and outcomes of IgG4-related idiopathic orbital inflammatory disease: from a large southern China-based cohort

PURPOSE

To investigate the clinical features and treatment outcomes of IgG4-related ophthalmic disease (IgG4-ROD) among idiopathic orbital inflammatory disease (IOID) patients.

METHODS

The medical records of 165 biopsy-proven IOID patients were retrospectively reviewed. Biopsy specimens were immunostained to detect IgG4 and IgG, and data regarding the clinicopathologic features, treatment outcomes, and recurrence were analyzed.

RESULTS

Among the 165 IOID patients enrolled, 100 (60.6%) were histopathologically IgG4-positive. The IgG4-positive patients had a lower rate of painful swelling or mass (17.0% versus 33.8%, p = 0.013), a longer symptom duration (p = 0.070), and a lower proportion of eyelid hyperemia (39.0% versus 58.5%, p = 0.014) than the IgG4-negative patients. Increased Ki-67 expression (15.02 ± 6.86%, p < 0.001) was observed in the IgG4-positive patients with characteristic pathological manifestations (more lymphocyte infiltration, nodular plasma cell infiltration, and follicular hyperplasia). IgG4-positive group had a higher recurrence rate in the subgroup of patients treated with surgery plus oral glucocorticoids (p = 0.046), and combined radiotherapy group has a higher cumulative proportion with recurrence (p = 0.011).

CONCLUSION

Over 60% of biopsy-proven IOID were classified as IgG4-ROD with a stronger proliferation potential. Additional radiotherapy after surgical debulking with oral corticosteroids still has a higher relapse rate, and more effective treatments are needed to prevent recurrence.

Analysis of Innate and Adaptive Immunological Characteristics in Patients with IgG4-Related Disease

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a systemic immunological disorder characterized by fibro-inflammatory conditions; however, the pathobiology of IgG4-RD has not been fully identified.

OBJECTIVE

This study aimed to analyze systemic differences of innate and adaptive immune cells from healthy controls and patients with IgG4-RD.

METHODS

Healthy controls (n = 9) and IgG4-RD patients (n = 7) were recruited with informed consent. Peripheral blood was collected from healthy controls and IgG4-RD patients, and three blood samples from IgG4-RD patients were re-collected two months after the last rituximab (RTX) treatment. The various immune cells and cytokine productions were measured by flow cytometry.

RESULTS

Blood CD14+ monocytes and steady-state follicular helper T cells were increased in patients with IgG4-RD. However, there were no changes in other immune cell populations, including B cells, CD4 T cells, CD8 T cells, and innate lymphoid cells. Also, the TGF-β-producing CD14+ monocytes were significantly augmented in patients with IgG4-RD. Two months after RTX treatment, total B cells (CD19+) were depleted; however, the expressions of TGF-β from CD14+ monocytes remained unchanged.

CONCLUSION

These findings showed that IgG4-RD is related to the increment of CD14+ monocytes. Besides, controlling increased TGF-β-producing CD14+ monocytes with RTX treatment might be a conducive way to regulate IgG4-RD.

Clinicopathological differential diagnosis of IgG4-related disease: A historical overview and a proposal of the criteria for excluding mimickers of IgG4-related disease

IgG4-related disease (RD) is a relatively new entity, which was first proposed in 2001. Since then, clinical and pathological characteristics of the disease have been investigated. As IgG4-RD has been studied extensively, the diagnostic criteria for IgG4-RD of each organ and the comprehensive diagnostic criteria for IgG4-RD have also been developed. However, one of the biggest challenges in the field is distinguishing between IgG4-RD and mimickers, which show overlapping features with IgG4-RD. It is now known that some non-IgG4-RDs may meet the diagnostic criteria of IgG4-RD and can be misdiagnosed as IgG4-RD. However, accurate diagnosis is crucial, as the treatments for IgG4-RD and those for other diseases that may be misdiagnosed as IgG4-RD are different. This prompted us to create and propose comprehensive exclusion criteria for IgG4-RD. In this review, we have described the comprehensive exclusion criteria for IgG4-RD, with a historical overview of the disease. These exclusion criteria were recently created by the Research Program for Intractable Disease of the Ministry of Health, Labor, and Welfare of Japan, All Japan IgG4 team, to support correct and accurate diagnosis of IgG4-RD.

Abundant a proliferation-inducing ligand (APRIL)-producing macrophages contribute to plasma cell accumulation in immunoglobulin G4-related disease

Background

This study aimed to investigate the contribution of a proliferation-inducing ligand (APRIL), a member of the tumor necrosis factor (TNF) superfamily implicated in plasma cell survival, to the development of plasma cell–rich lesions in immunoglobulin G4–related disease (IgG4-RD).

Methods

We performed immunohistochemical staining for APRIL with Stalk-1 and Aprily-8 antibodies specifically recognizing APRIL-producing cells and secreted APRIL, respectively, in renal and submandibular lesions of IgG4-RD in comparison with those of Sjögren’s syndrome and sialolithiasis.

Results

Numerous Stalk-1-positive APRIL-producing cells were detectable in lesions of IgG4-RD. These cells, identified as CD163-positive M2 macrophages, secreted APRIL that distributed close to and even on infiltrating plasma cells. In contrast, APRIL-producing cells and the secreted form of APRIL were rarely detectable in lesions of Sjögren’s syndrome or sialolithiasis. Notably, APRIL expression decreased concomitantly with the level of plasma cell infiltration after successful glucocorticoid treatment.

Conclusions

Abundant infiltration into tissue lesions of APRIL-producing M2 macrophages and retention of secreted APRIL in plasma–cell–rich areas support a role for APRIL in the pathogenesis of plasma cell–rich lesions in IgG4-RD.

Immunoglobulin G4-related chronic sclerosing sialadenitis: An emerging entity

Chronic sclerosing sialadenitis is associated with the immunoglobulin G4 (IgG4)-related disease (RD) spectrum. IgG4-RD is a newly recognized immunomediated fibroinflammatory condition characterized by several features: a tendency to form tumefactive lesions at multiple sites, lymphoplasmacytic infiltrate, fibrosis and obliterative phlebitis. Often but not always, the serum IgG4 concentrations are also elevated. Immunohistochemistry for IgG4 is helpful to clinch the diagnosis. Here, we describe a case of 65-year-old male with IgG4-related chronic sclerosing sialadenitis of the s ubmandibular gland. We have discussed the histopathological criteria to diagnose this entity.

Clinical features and mechanistic insights regarding IgG4-related dacryoadenitis and sialoadenitis: a review

Immunoglobulin G4-related disease (IgG4-RD), recognized only recently as a single diagnostic entity, is a chronic inflammatory condition of unknown etiology. The diagnosis of IgG4-RD relies heavily on histopathological analysis and the correlation of histology findings with clinical, serological, and radiological data. CD4⁺ T and B cells, including IgG4-expressing plasmablasts, constitute the major inflammatory cell populations in IgG4-RD and are believed to cause organ damage and tissue fibrosis. Patients with IgG4-RD, who have active, untreated disease, exhibit marked expansion of IgG4-secreting plasmablasts in the blood. Important mechanistic insights correlated with the pathogenesis of IgG4-RD have been disclosed in recent years through the application of novel molecular biology approaches, including next-generation and single-cell RNA sequencing. Exploration of the interactions between these CD4⁺ T cells and cells of the B lymphocyte lineage is critical to understanding the pathophysiology of IgG4-RD. The establishment of pathogenic T cell clones and the identification of antigens specific to these clones constitute the first steps in determining the pathogenesis of this disease. This review focuses on clinical features and mechanistic insights regarding IgG4-related dacryoadenitis and sialoadenitis, from a perspective suitable for oral and maxillofacial surgeons.

Spontaneous Regression of Swollen Submandibular Glands in IgG4-Related Disease

Background

IgG4-related disease is a new clinical entity frequently associated with swelling of the submandibular glands (SMGs). The long-term outcome of SMG swelling without steroid therapy remains unknown.

Objective

To examine whether swollen SMGs spontaneously regress without steroid therapy in the context of IgG4-related disease and to identify biomarkers that can predict the spontaneous regression of SMG swelling.

Methods

The SMG volume of 49 patients diagnosed with IgG4-related disease was calculated by measuring the axial and coronal planes of computed tomography scans. The change in SMG volume over time was measured and examined by treatment regimen, clinical data, and serum complement level.

Results

We found 28 of 49 (57%) IgG4-related disease patients to have swollen SMGs, with 15 of 20 (75%) of the swollen SMGs regressing without steroid therapy. The time required for the SMGs swelling to regress was significantly shorter in the steroid therapy group than in the no-steroid therapy group. Serum complement components at the initial visit were significantly lower in the regressed SMG group than in the nonregressed SMG group.

Conclusion

We observed 75% of swollen SMGs spontaneously regressed in patients with IgG4-related disease. The time required for the swollen SMGs to regress was longer in patients without steroid therapy than in those with steroid therapy. Serum complement level could be used as a predictor for the spontaneous regression of swollen SMGs in patients with IgG4-related disease.

Perirenal capsule and scrotal involvement in immunoglobulin G4-related kidney disease: case-based review

Immunoglobulin G4-related disease (IgG4-RD) is a chronic, immune-mediated-, systemic disease that is characterized by IgG4 plasma cell infiltration with fibrotic changes in various organs. The most affected organs are pancreas and salivary glands. Kidney can be rarely involved, and is usually represented as a renal mass and organomegaly. Usually, elevated levels of serum IgG4 more than 135 mg/dl with organ-specific features and biopsy results showing enriched infiltration of IgG4-positive plasma cells are needed to diagnose the disease. However, we experienced two unusual cases of IgG4-RD involving kidney. IgG4-related kidney disease (IgG4-RKD) was first reported as an extra pancreatic feature of autoimmune pancreatitis(AIP) in 2004. Herein, we describe two cases of such unique presentation of IgG4RKD and a literature review focusing on clinicopathologic features of IgG4RKD. Our cases are distinct in the fact that IgG4RD invades unusual organs such as perinephric capsule or scrotum. We reported the patient who showed extinct perirenal capsule invasion with multi-organ involvement including exocrine glands in comparison to previous IgG4RKD that often involved in renal parenchyma and renal pelvis lesions. And the other patient had scrotal invasion with multifocal renal parenchymes. Referring to the features observed in these two cases, we could propose that as every organ can be related to IgG4RD, we propose clinicians to confirm the disease using imaging, serologic, and pathologic studies. We also reviewed previous reports of IgG4-RKD and summarized diverse imaging findings and pathologic features.

Salivary Gland Pathology in IgG4-Related Disease: A Comprehensive Review

IgG4-related disease (IgG4-RD) is a rare fibroinflammatory condition that can affect almost any organ, characterized by swollen lesions and often by eosinophilia and elevated serum IgG4 concentrations. The diagnosis of IgG4-RD is a challenging task: in fact, single or multiple organs can be affected and clinical, serological, and histological findings can be heterogeneous. In IgG4-RD, the involvement of salivary glands is observed in 27% to 53% of patients. Several organ-specific conditions, now recognized as different manifestations of IgG4-related sialadenitis (IgG4-RS), were viewed in the past as individual disease entities. The study of salivary glands may sometimes be complex, because of the number of pathological conditions that may affect them, often with overlapping clinical pictures. Integration of different imaging techniques is often required in the case of swelling of salivary glands, even though biopsy remains the gold standard for a definite diagnosis of IgG4-RS. Thus, in this review, we discuss new insights in the pathogenesis of IgG4-RD, focusing on its clinical aspects and the tools that are currently available for a correct differential diagnosis when the salivary glands are involved.

Mikulicz's Disease: A New Perspective and Literature Review

PURPOSE

To report the clinical and pathophysiologic features of two patients with Mikulicz's disease and to further characterize recommendations for diagnosis and management with a review of the literature.

METHODS

Retrospective nonrandomized consecutive case series, Jules Stein Eye Institute, David Geffen School of Medicine at UCLA.

RESULTS

Mikulicz's disease is characterized by symmetric lacrimal, parotid, and submandibular gland enlargement with associated lymphocytic infiltrations. The authors noted two cases of Mikulicz's disease. The diagnosis of Mikulicz's disease was based on the following criteria: 1) symmetric and persistent swelling of the lacrimal glands and either or both of the major salivary glands (parotid and submandibular); and 2) the exclusion of other diseases that may mimic this presentation, such as sarcoidosis, viral infection, or lymphoproliferative disorders.

CONCLUSIONS

Mikulicz's disease is a condition in which there is bilateral lacrimal and salivary gland swelling that is not associated with other systemic conditions. The condition is self-limiting and most often, the diagnosis is a clinical one. Previously, Mikulicz's disease was often considered as a subtype of Sjögren's syndrome (SS). Clinical and immunologic differences between Mikulicz's disease and SS may warrant further consideration of Mikulicz's disease as a specific autoimmune phenomenon separate from SS, and Mikulicz's disease may be amenable to different treatment modalities than those employed in patients with SS.

Th1/Th2 Immune Balance and Other T Helper Subsets in IgG4-Related Disease

IgG4-related disease (IgG4-RD) is a systemic disease characterized by elevated serum IgG4 levels and a strong infiltration of IgG4-positive plasma cells in various organs. IgG4-RD patients also frequently suffer from allergic diseases, including asthma and atopic dermatitis. It is well known that T helper type 2 (Th2) cells have an important role in the initiation of allergic diseases, and Th2 cytokines such as interleukin (IL)-4 and IL-13 promote class switching to IgG4. Therefore, IgG4-RD is considered to be a Th2-predominant disease. However, other Th subsets, including regulatory T cells and T follicular helper cells, have recently received increasing attention with regard to the pathogenesis of IgG4-RD. Exploring the interconnected network of Th subsets in IgG4-RD is a highly promising field of investigation. In this review, we focus on the localization and functions of individual Th subsets to clarify the involvement of these cells in the pathogenesis of IgG4-RD.

B cell receptor signaling pathway involved in benign lymphoepithelial lesions of the lacrimal gland

AIM

To detect the expression of B cell receptor signaling pathway (BCRSP) in lacrimal gland benign lymphoepithelial lesions (LGBLEL).

METHODS

Gene microarray was used to compare whole-genome expression in lacrimal gland tissues from LGBLEL patients to tissues from orbital cavernous hemangioma (control tissues). Expression of BCRSP was confirmed by polymerase chain reaction (PCR) and immunohistochemistry.

RESULTS

The expression of 22 genes of the BCRSP increased significantly in LGBLEL patients. PCR analysis showed that CD22, CR2, and BTK were all highly expressed in LGBLEL tissues. Immunohistochemical analysis showed that CR2 protein was present in LGBLEL, but CD22 and BTK proteins were negative. CR2, CD22, and BTK were not observed in the orbital cavernous hemangiomas with either PCR or immunohistochemistry.

CONCLUSION

BCRSP might be involved in the pathogenesis of LGBLEL.

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.

Recent advances in knowledge regarding the head and neck manifestations of IgG4-related disease

IgG4-related disease (IgG4-RD) is a chronic inflammatory disorder, characterized by elevated serum IgG4 levels as well as abundant infiltration of IgG4-positive plasmacytes and fibrosis in various organs, including the head and neck region. In particular, the salivary glands, orbit, and thyroid are common sites of disease involvement. IgG4-RD is diagnosed based on various clinical, serological, and histopathological findings, none of which are pathognomonic. Hence, various differential diagnoses, which exhibit elevated serum IgG4 levels and infiltration of IgG4-postive cells into tissues, need to be excluded, especially malignant diseases and mimicking disorders. Systemic corticosteroids are generally effective in inducing IgG4-RD remission; however, recurrent or refractory cases are common. In addition, although the pathogenic mechanisms of IgG4-RD remain unclear, an antigen-driven inflammatory condition is believed to be involved. Recent studies have indicated the important pathogenic role of B cell/T cell collaboration and innate immunity in this disease. Nevertheless, additional research and discussions are needed to resolve many remaining questions. In this review, we provide an overview of the recent insights on the history, clinical features, diagnosis, and treatment of IgG4-RD in the head and neck region. Furthermore, we have also addressed the pathogenesis of this disease.

Sequential Evaluation of Pancreato-Biliary Findings in a Case with IgG4-Associated Cholangiopathy and Autoimmune Pancreatitis during Corticosteroid Treatment

BACKGROUND

Immunoglobulin G4 (IgG4)-associated diseases mostly involve the pancreaticobiliary tree and pancreatic parenchyma. This disease complex is characterized by marked response to corticosteroid therapy and response to steroids is incorporated in the diagnostic algorithm of IgG4 associated diseases. However, there is much unknown about the sequences and duration of healing during the corticosteroid therapy in the literature.

CASE REPORT

In this case report, we report a young male patient with IgG4 associated extrahepatic biliary stricture and autoimmune pancreatitis successfully treated with corticosteroids. Recovery in the laboratory and radiological findings seemed to correlate well with the decrease in serum IgG4 levels in this patient. We also discussed sequences and the duration of healing in the pancreaticobiliary tree and pancreatic parenchymal manifestations in this case report.

CONCLUSION

There is a gap in our knowledge about the evaluation of response criteria after steroid trial with regard to the duration and sequences of healing in the pancreaticobiliary involvement in diagnosing IgG4-related biliary and pancreatic diseases.

Gallium SPECT/CT in evaluation of IgG4-related disease: A case report and literature review

BACKGROUND

The clinical picture of IgG4-related sclerosing disease (IgG4-RSD) may mimic lymphoma, and should be in the differential diagnosis of patients with this clinical picture.

CASE SUMMARY

A 32-year-old female had recurrent swelling of both eyelids for more than 15 years. Examination revealed elastic, firm, swollen lacrimal glands about 2-3 cm in diameter that was not painful. Head and orbits magnetic resonance imaging (MRI) showed mass lesions over the bilateral lacrimal glands, submandibular glands, and left foramen of ovale. The differential diagnosis included lymphoid tissue, inflammatory masses, and lymphoma. Gallium single-photon emission computed tomography/computed tomography (SPECT/CT) showed uptake in the bilateral lacrimal glands, right parotid and bilateral submandibular glands, bilateral perirenal region, mediastinal, prevertebral, paraaortic, lumbar, bilateral pelvic (including internal iliac chain) lymph nodes, anterior aspect of right 3rd rib, and lateral aspect of left 6th rib. CT showed multiple enlarged lymph nodes in the mediastinum, right pulmonary hilum, prevertebral space of the thoracolumbar spine, retroperitoneal paraaortic area, bilateral parailiac areas, and bilateral perirenal spaces. Antinuclear and anti-SSA/SSB antibodies were negative, and the serum IgG4 level was 740 mg/dL (normal, 8-140 mg/dL). Right parotid gland biopsy showed abundant IgG4-positive plasma cells. Mikulicz disease (IgG4-related sclerosing disease) was diagnosed and she received glucocorticoid treatment. Follow-up CT and MRI showed with resolved eyelid swelling and perirenal mass lesions. Follow-up gallium scan was normal.

CONCLUSION

Gallium SPECT/CT can be a useful tool for initial and follow-up evaluation of IgG4-RSD.

In vitro studies implicate an imbalanced activation of dendritic cells in the pathogenesis of murine autoimmune pancreatitis

Objectives

MRL/MpJ mice spontaneously develop an autoimmune pancreatitis (AIP) and are widely used as a model to study the genetic, molecular and immunological basis of the disease. Here, we have addressed the question whether distinctive features of their dendritic cells (DCs) may predispose MRL/MpJ mice to the chronic inflammation.

Methods

Pancreatic lesions were analyzed employing histological methods. Cohorts of young (healthy) MRL/MpJ mice, adult (sick) individuals, and AIP-resistant CAST/EiJ mice were used to establish cultures of bone marrow (BM)-derived conventional DCs (cDCs). The cells were subsequently characterized regarding the expression profile of CD markers and selected genes, proliferative activity as well as cytokine secretion.

Results

In pancreatic lesions, large numbers of cells expressing the murine DC marker CD11c were detected in close spatial proximity to CD3⁺ cells. A high percentage of BM-derived cDCs from adult MRL/MpJ mice expressed typical markers of DC maturation (such as CD83) already prior to a treatment with lipopolysaccharide (LPS). After LPS-stimulation, cDC cultures of both MRL/MpJ mouse cohorts contained more mature cells, proliferated at a higher rate and secreted less interleukin-10 (but also less pro-inflammatory cytokines) than cultures of CAST/EiJ mice. Compared with corresponding cultures of the control strain, LPS-free cultured cDCs from MRL/MpJ mice expressed less mRNA of the inhibitory receptor triggering receptor expressed on myeloid cells 2 (trem2).

Conclusions

BM-derived cDCs from AIP-prone MRL/MpJ mice display functional features that are compatible with the hypothesis of an imbalanced DC activation in the context of murine AIP.

Lesional CD4+ IFN-γ+ cytotoxic T lymphocytes in IgG4-related dacryoadenitis and sialoadenitis

OBJECTIVES

IgG4-related disease (IgG4-RD) is a chronic, systemic, inflammatory condition of unknown aetiology. We have recently described clonally expanded circulating CD4⁺ cytotoxic T lymphocytes (CTLs) in IgG4-RD that infiltrate affected tissues where they secrete interleukin (IL)-1β and transforming growth factor -β1 (TGF-β1). In this study, we sought to examine the role of CD4⁺ CTLs in the pathogenesis of IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS) and to determine whether these cells secrete interferon-gamma (IFN-γ) at lesional sites.

METHODS

Salivary glands of 25 patients with IgG4-DS, 22 patients with Sjögren's syndrome (SS), 12 patients with chronic sialoadenitis (CS) and 12 healthy controls were analysed in this study. Gene expression analysis was performed on submandibular glands (SMGs) from five patients with IgG4-DS, three with CS and three healthy controls. Infiltrating CD4⁺ CTLs were examined by quantitative multicolour imaging in tissue samples from 20 patients with IgG4-DS, 22 patients with SS, 9 patients with CS and 9 healthy controls.

RESULTS

In IgG4-DS tissues, nine genes associated with CD4⁺ CTLs were overexpressed. The expression of granzyme A (GZMA) mRNA was significantly higher in samples from patients with IgG4-RD compared with corresponding tissues from SS and healthy controls. Quantitative imaging showed that infiltrating CD4⁺ GZMA⁺ CTLs were more abundant in patients with IgG4-DS than in the other groups. The ratio of CD4⁺GZMA⁺ CTLs in SMGs from patients with IgG4-DS correlated with serum IgG4 concentrations and the number of affected organs. A large fraction of CD4⁺GZMA⁺ CTLs in SMGs from patients with IgG4-DS secreted IFN-γ.

CONCLUSIONS

The pathogenesis of IgG4-DS is associated with tissue infiltration by CD4⁺GZMA⁺ CTLs that secrete IFN-γ.

[IgG4-related salivary gland lesions]

AIM

To provide the demographic, clinical, laboratory, radiological, morphological, and immunomorphological characteristics of IgG4-related sialoadenitis (IgG4-S), which allow the differential diagnosis with neuroendocrine, granulomatous, blood cancer lesions of the salivary gland (SG).

SUBJECTS AND METHODS

In the period 2004 to 2014, IgG4-S was diagnosed in 32 (11%) out of 289 patients with significantly enlarged parotid and submandibular glands (PG and SMG). Only 4 (9%) patients had isolated IgG4-related disease (IgG4-D) whereas involvement of a few organs ran as an IgG4-SD systemic disease in 29 (91%) patients.

RESULTS

There was a slight preponderance of women with a median onset age of 42 years. Enlargement of the SMG (52.7%), lesions of the nasal cavity and paranasal sinuses (37.2%), and enlargement of the lacrimal gland and orbital pseudotumors (31%) are the most common clinical manifestations at disease onset. A follow-up study indicated that along with involvements of SMG (97%), PG (72%), eye sockets (72%), nasal cavity and paranasal sinuses (56%), one third of the patients were found to have generalized lymphadenopathy, to frequently develop pulmonary, hepatic, pancreatic, renal injuries; and the disease ran within IgG4-SD. The laboratory manifestations were characterized by moderate eosinophilia and elevated blood IgE levels in one-third of the patients and by moderately higher erythrocyte sedimentation rate and hypergammaglobulinemia in 50%. The increased blood level of IgG (84%) and its subclass IgG4 (86.4%) is an indication for further verification of IgG4-D in patients with involvement of the major SG. Immunohistochemical examination, by measuring the concentration of IgG4-secreting plasma cells (PCs), and determination of B-cell clonality in biopsy specimens should be done to verify a diagnosis with IgG4-D.

CONCLUSION

The determination of blood IgG4 (>2 g/l) in patients with considerably enlarged major SG may suggest the presence of IgG4-S. Minimally invasively incised PG and SMG biopsies with their subsequent morphological and immunomorphological examinations should be performed to make an accurate diagnosis. More than 40% of IgG4-secreting PCs detected in SG tissue is evidence to diagnose IgG4-D.

IgG4-related disease: A relatively new concept for clinicians

IgG4-related disease (IgG4-RD) is a recently recognized chronic fibrotic inflammation, which can affect almost every organ, and may come to clinical attention first due to visible organ swelling or organ dysfunction, or is identified incidentally by imaging and specific biopsy. The disorder has an allergic background and is immune-mediated. Up-regulated responses of T helper 2 and T regulatory cells and their cytokines play a major role in disease progression. About 30-50% of patients are atopic or have mild eosinophilia. IgG4-RD predominantly affects middle-aged male patients. The cornerstones of diagnosis of the disease are compatible clinical features and typical histopathology. Swelling of salivary and lacrimal glands, lymphadenopathy, and type 1 autoimmune pancreatitis (AIP) are the most common manifestations of the disease. However, other tissues and organs, such as retroperitoneum, lung, kidney, aorta, upper airways, thyroid gland, meninges, heart, mesenterium and skin may be involved. Typical histopathology is lymphoplasmacytic infiltration abundant in IgG4-positive plasma cells, storiform-type fibrosis, and obliterative phlebitis. Elevated serum IgG4 concentration supports the diagnosis. Characteristic imaging features such as a "capsule-like rim" surrounding the pancreatic lesions is highly specific to type 1 AIP. 18F-fluorodeoxyglucose positron emission tomography/computed tomography enables mapping the sites of inflammation, permits evaluation of the extent of the disease, helps in guiding biopsy decision, and may be used in monitoring response to treatment. Glucocorticoids alone or in combination with B-cell depletion with rituximab induces prompt clinical response to IgG4-RD. This article reviews the current understanding, different clinical manifestations, and approaches to diagnosis and treatment of IgG4-RD.

Immunogenetics of IgG4-Related AIP

Autoimmune pancreatitis (AIP) is a unique form of chronic pancreatitis characterized by high serum IgG4 concentration and a variety of complicating extra-pancreatic lesions. AIP has the features of a complex disease that is caused by multifactorial genes. However, the genetic factors underlying AIP have not been elucidated conclusively. Association studies by the candidate-gene approach and genome-wide association studies (GWAS) have revealed several susceptibility genes for AIP, including HLA DRB1*04:05-DQB1*04:01, FCRL3, CTLA4, and KCNA3, albeit in small-scale analyses. Thus, GWAS of large sample sizes and multinational collaborative meta-analyses are needed to identify the precise genetic variants that are associated with AIP onset. Systems genetics approaches that integrate DNA sequencing, expression quantitative trait locus (eQTL) mapping, proteomics, and metabolomics will also be useful in clarifying the pathogenesis of AIP.

The Histopathology of IgG4-Related Disease

IgG4-related disease is a multi-organ immune-mediated chronic fibroinflammatory condition characterized by elevated serum IgG4 concentrations, tumefaction, and tissue infiltration by IgG4-positive plasma cells. The exact etiology of IgG4-related disease remains unclear with no known role of the IgG4 molecule itself being identified. Although the pancreas and salivary glands are the main organs affected, the involvement of other organs has also been reported. This multi-organ disease mimics a large number of malignant, infectious, and inflammatory disorders; therefore, a prompt differential diagnosis is important for selecting the right therapeutic strategy. Early steroid therapy assists in preventing tissue fibrosis, parenchymal extinction, and severe functional impairments in the affected organs. The definitive and prompt diagnosis of IgG4-related disease requires both histopathological confirmation and clinicopathological correlations. A histopathological examination is mandatory to exclude neoplastic or inflammatory conditions that mimic IgG4-related disease. The histological changes that occur are basically similar in any organ manifestation, with several site-specific findings being recognized. This chapter summarizes general rules for the pathological examination of IgG4-related disease, as well as the histopathological features and differential diagnoses of major organ manifestations.

Multiple Coronary Artery Aneurysms and Thoracic Aortitis Associated with IgG4-related Disease

A 60-year-old man was admitted due to the onset of right coronary artery (RCA) aneurysms. Coronary angiography showed two RCA aneurysms and focal stenosis with limitations in the blood flow. Balloon angioplasty was performed. However, the follow-up coronary angiography showed restenosis, an enlarged proximal aneurysm and a newly formed aneurysm. The serum immunoglobulin G4 level was elevated to 1,350 mg/dL and fluorodeoxyglucose positron emission tomography showed increased uptake in the ascending aorta, so the patient was diagnosed with immunoglobulin G4-related vascular disease. The prevention of further enlargement of the aneurysms and an improvement in the RCA flow were achieved with steroid therapy. Steroid therapy may therefore be effective for immunoglobulin G4-related vascular disease.

Ultrasonographic Features of Immunoglobulin G4-Related Sialadenitis

The aim of this study was to determine the role of ultrasonography in the diagnosis and follow-up evaluation of immunoglobulin G4-related sialadenitis. In this study, 42 patients with immunoglobulin G4-related sialadenitis underwent ultrasonography of the parotid and submandibular glands, and the sonographic appearance was compared with the pathologic findings. Post-treatment ultrasonographic appearance was compared with the pre-treatment findings in 30 patients who received immunomodulatory therapy. The ultrasonographic appearance of the affected glands was divided into five patterns: superficial hypo-echoic, multiple hypo-echoic foci, whole-gland heterogeneity, space occupying and normal echo. Histopathologic examination revealed marked lymphoplasmacytic inflammation and inter-lobular fibrosis, which were more severe in the superficial than deep portion of the affected glands. After treatment, the volume of the affected gland decreased significantly, the internal echo became more homogeneous and the superficial hypo-echoic area disappeared or was reduced. In conclusion, ultrasonography may play an important role in the diagnosis and follow-up evaluation of immunoglobulin G4-related sialadenitis.

Characteristics, diagnosis and therapeutic strategies for IgG4-related orbital disease

Thanks to detailed studies conducted in recent years, a new disease syndrome was identified in 2001. It is known as a IgG4-related disease and its differentiation is based on the analysis of IgG4 levels in the affected tissues. The IgG4-related disease is considered to be a generalized pathological process involving a wide spectrum of various disorders that may affect distant organs. Orbital IgG4-related disease is a recently reported issue that may prove important for the elucidation of the etiology of idiopathic, lymphoplasmacytic or fibrotic disorders of various organs, including the orbits. In this article, we are describing epidemiology and differential diagnostics of IgG4-related orbital disease with particular focus on pseudotumors, MALT lymphomas and lymphocyte/plasma cell infiltrations of the orbit. We are also discussing therapeutic possibilities currently available in the management of the disease.

Quantitative Trait Locus Analysis Implicates CD4⁺/CD44high Memory T Cells in the Pathogenesis of Murine Autoimmune Pancreatitis

The mouse strain MRL/MpJ is prone to spontaneously develop autoimmune pancreatitis (AIP). To elucidate the genetic control towards the development of the phenotype and to characterize contributions of immunocompetent cell types, MRL/MpJ mice were interbred with three additional strains (BXD2/TYJ, NZM2410/J, CAST/EIJ) for four generations in an advanced intercross line. Cellular phenotypes were determined by flow cytometric quantification of splenic leukocytes and complemented by the histopathological evaluation of pancreatic lesions. An Illumina SNP array was used for genotyping. QTL analyses were performed with the R implementation of HAPPY. Out of 41 leukocyte subpopulations (B cells, T cells and dendritic cells), only three were significantly associated with AIP: While CD4⁺/CD44^high memory T cells and CD4⁺/CD69⁺ T helper (Th) cells correlated positively with the disease, the cytotoxic T cell phenotype CD8⁺/CD44^low showed a negative correlation. A QTL for AIP on chromosome 2 overlapped with QTLs for CD4⁺/CD44^high and CD8⁺/CD44^high memory T cells, FoxP3⁺/CD4⁺ and FoxP3⁺/CD8⁺ regulatory T cells (Tregs), and CD8⁺/CD69⁺ cytotoxic T cells. On chromosome 6, overlapping QTLs for AIP and CD4⁺/IL17⁺ Th17 cells and again FoxP3⁺/CD8⁺ Tregs were observed. In conclusion, CD4⁺/CD44^high memory T cells are the only leukocyte subtype that could be linked to AIP both by correlation studies and from observed overlapping QTL. The potential role of this cell type in the pathogenesis of AIP warrants further investigations.

Effectiveness of imaging modalities for screening IgG4-related dacryoadenitis and sialadenitis (Mikulicz's disease) and for differentiating it from Sjögren's syndrome (SS), with an emphasis on sonography

INTRODUCTION

The aim of this study was to clarify the effectiveness of various imaging modalities and characteristic imaging features in the screening of IgG4-related dacryoadenitis and sialadenitis (IgG4-DS), and to show the differences in the imaging features between IgG4-DS and Sjögren's syndrome (SS).

METHODS

Thirty-nine patients with IgG4-DS, 51 with SS and 36 with normal salivary glands were enrolled. Images of the parotid and submandibular glands obtained using sonography, 2-[(18)F]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT), computed tomography (CT) and magnetic resonance imaging (MRI) were retrospectively analyzed. Six oral and maxillofacial radiologists randomly reviewed the arranged image sets under blinded conditions. Each observer scored the confidence rating regarding the presence of the characteristic imaging findings using a 5-grade rating system. After scoring various findings, diagnosis was made as normal, IgG4-DS or SS, considering all findings for each case.

RESULTS

On sonography, multiple hypoechoic areas and hyperechoic lines and/or spots in the parotid glands and obscuration of submandibular gland configuration were detected mainly in patients with SS (median scores 4, 4 and 3, respectively). Reticular and nodal patterns were observed primarily in patients with IgG4-DS (median score 5). FDG-PET/CT revealed a tendency for abnormal (18)F-FDG accumulation and swelling of both the parotid and submandibular glands in patients with IgG4-DS, particularly in the submandibular glands. On MRI, SS had a high score regarding the findings of a salt-and-pepper appearance and/or multiple cystic areas in the parotid glands (median score 4.5). Sonography showed the highest values among the four imaging modalities for sensitivity, specificity and accuracy. There were significant differences between sonography and CT (p = 0.0001) and between sonography and FDG-PET/CT (p = 0.0058) concerning accuracy.

CONCLUSIONS

Changes in the submandibular glands affected by IgG4-DS could be easily detected using sonography (characteristic bilateral nodal/reticular change) and FDG-PET/CT (abnormal (18)F-FDG accumulation). Even inexperienced observers could detect these findings. In addition, sonography could also differentiate SS. Consequently, we recommend sonography as a modality for the screening of IgG4-DS, because it is easy to use, involves no radiation exposure and is an effective imaging modality.

A case of mantle cell lymphoma presenting as IgG4-related dacryoadenitis and sialoadenitis, so-called Mikulicz's disease

Background

Mantle cell lymphoma (MCL) is a relatively uncommon type of non-Hodgkin lymphoma. It develops in the outer edge of a lymph node called the mantle zone. In contrast, IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS) is characterized by elevated serum IgG4 and persistent bilateral enlargement of lacrimal glands (LGs) and salivary glands (SGs), with infiltration of IgG4-positive plasma cells. Recent studies indicated the importance of differentiation between IgG4-DS and malignant lymphoma.

Case presentation

An 82-year-old man was suspected of IgG4-DS because of a high serum IgG level (2174 mg/dL) and bilateral swelling of LGs and SGs. Lip biopsy and fine needle biopsy of submandibular gland were performed, and subsequently, MCL was diagnosed through the histopathological findings.

Conclusions

MCL most commonly occurs in the Waldeyer ring, but rarely in the stomach, spleen, skin, LG, and SG. We report an unusual case of MCL involving LGs and SGs mimicking IgG4-DS, which suggests that IgG4 testing may be useful in the differentiation of IgG4-DS in the presence of bilateral swelling of LGs or SGs.

Recent Advances in Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis that is characterized clinically by frequent presentation with obstructive jaundice, histologically by a dense lymphoplasmacytic infiltrate with fibrosis, and therapeutically by a dramatic response to corticosteroid therapy. Two distinct diseases, type 1 and type 2 AIP, share these features. However, these 2 diseases have unique pancreatic histopathologic patterns and differ significantly in their demographic profiles, clinical presentation, and natural history. Recognizing the popular and long-standing association of the term "AIP" with what is now called "type 1 AIP," we suggest using "AIP" solely for type 1 AIP and to acknowledge its own distinct disease status by using "idiopathic duct-centric chronic pancreatitis" (IDCP) for type 2 AIP. AIP is the pancreatic manifestation of immunoglobulin G4-related disease (IgG4-RD). The etiopathogenesis of AIP and IgG4-RD is largely unknown. However, the remarkable effectiveness of B-cell depletion therapy with rituximab in patients with AIP and IgG4-RD highlights the crucial role of B cells in its pathogenesis. IDCP is less commonly recognized, and little is known about its pathogenesis. IDCP has no biomarker but is associated with inflammatory bowel disease in ~25% of patients. Recently, the international consensus diagnostic criteria for AIP identified combinations of features that are diagnostic of both diseases. Both AIP and IDCP are corticosteroid responsive; however, relapses are common in AIP and rare in IDCP. Therefore, maintenance therapy with either an immunomodulator (eg, azathioprine, 6-mercaptopurine, or mycophenolate mofetil) or rituximab is often necessary for patients with AIP. Long-term survival is excellent for both patients with AIP and patients with IDCP.

IgG4-related disease: dataset of 235 consecutive patients

Immunoglobulin G4-related disease (IgG4-RD) is a recently discovered systemic condition, in which various organ manifestations are linked by a similar histological appearance. Our knowledge of this condition is still fragmented, as most studies have examined only a few dozen patients or focused on a particular organ manifestation. This study was conducted to learn the demography and patient characteristics of IgG4-RD using a large cohort. A total of 235 consecutive patients with IgG4-RD, diagnosed in 8 general hospitals in the same medical district, were identified by searching the institutions' radiology database. Inclusion criteria were histology-proven IgG4-RD according to the Pathology Consensus Statement and/or definitive type 1 autoimmune pancreatitis meeting the International Consensus Diagnostic Criteria. Clinical notes and images of selected patients were retrospectively reviewed. All patients were adults (M/F = 4/1). The median age was 67 years (range 35-86). Nine tenths were diagnosed in their 50s to 70s. Among 486 manifestations identified in total, the most common was pancreatitis diagnosed in 142 patients (60%), followed by sialadenitis (34%), tubulointerstitial nephritis (23%), dacryoadenitis (23%), and periaortitis (20%). The majority of patients (95%) had at least 1 of the 5 most common manifestations. Male and female patients differed in their organ manifestations (periaortitis more common in males and sialodacryoadenitis more common in females). Serum IgG4 (normal ≤135 mg/dL) was elevated to >135 mg/dL in 208 patients (88%) and >270 mg/dL in 167 (71%). The IgG4 value was significantly higher in patients with multiorgan involvement than in those with a single manifestation (median 629 mg/dL vs 299 mg/dL, P < 0.01). Of 218 patients, for whom both IgG4 and IgG values were available, the IgG4/IgG ratio was raised to >10% in 194 (89%). Corticosteroids were effective, but the relapse rate was estimated to be 24% in the study period (median 37 months). During the follow-up, 15 malignant diseases were diagnosed in 13 patients (6%). This figure is similar to the incidence (12.9 cancers) expected from the Japanese nationwide study for cancer epidemiology (standardized incidence ratio 1.16). In conclusion, this reliable dataset could improve the characterization of IgG4-RD, particularly its unique demography and the frequency of each organ manifestation.

A case of marginal zone B cell lymphoma mimicking IgG4-related dacryoadenitis and sialoadenitis

Background

IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS), so-called Mikulicz’s disease, is characterized by elevated serum IgG4 and infiltration of IgG4-positive plasma cells in glandular tissues. Recently, several studies reported both malignant lymphoma developed on the background of IgG4-associated conditions and IgG4-producing malignant lymphoma (non-IgG4-related disease).

Case presentation

We report on the case of a 70-year-old man who was strongly suspected IgG4-DS because of high serum IgG4 concentration (215 mg/dl) and bilateral swelling of parotid and submandibular glands. Biopsies of cervical lymph node and a portion of submandibular gland were performed. These histopathological findings subsequently confirmed a diagnosis of marginal zone B cell lymphoma.

Conclusion

Differential diagnosis of IgG4-DS is necessary from other disorders, including Sjögren’s syndrome, sarcoidosis, Castleman’s disease, Wegener’s granulomatosis, lymphoma, and cancer. We suggest that biopsy of swollen lesions is important for a definitive diagnosis of IgG4-DS and discuss the mechanism of development in this case.