Abundant IgG4-positive plasma cell infiltration characterizes chronic sclerosing sialadenitis (Küttner's tumor)

MAML2-rearrranged sclerosing mucoepidermoid carcinoma of submandibular gland: an incidental finding in a patient with history of recurrent sialadenitis and Sjögren's syndrome

The Sclerosing subtype of mucoepidermoid carcinoma is rare, with only 39 cases reported in literature. We present a new case of sclerosing mucoepidermoid carcinoma (SMEC) with MAML2 rearrangements. A 49-year-old woman with Sjögren's syndrome experienced recurrent submandibular sialadenitis and sialolithiasis, leading to the removal of her right gland. Postoperative imaging revealed a calcified mass in her left gland which was subsequently resected. The pathologic examination revealed a well-defined tumor with extensive fibrous stroma, predominantly epidermoid cells, and occasional mucinous components. There was a dense lymphocytic and plasma cell infiltrate at the tumor's periphery. Immunohistochemistry was positive for p40 and CK7, few IgG4+ plasma cells. No eosinophils were identified. Fluorescence in situ hybridization (FISH) revealed rearrangement of the MAML2 (11q21) region. Adjuvant radiation was not recommended because of the patient's history of autoimmune diseases and the fact that the tumor was small, localized, and had negative resection margins. The patient was advised to undergo a repeat CT scan of the neck, scheduled for 3 months later. This case highlights the importance of considering SMEC in the differential diagnosis of patients with sialolithiasis or Sjögren's syndrome.

Clinical characteristics of chronic sclerosing sialadenitis as a distinctive entity from primary Sjögren's syndrome

Objective

This study aimed to elucidate the clinical and laboratory differences between chronic sclerosing sialadenitis (CSS) and primary Sjögren's syndrome (pSS), highlighting CSS as a distinct pathological entity within the spectrum of salivary gland pathology.

Methods

This retrospective, single-center study was conducted at Seoul St. Mary's Hospital between January 2000 and December 2022. Patients diagnosed with CSS via salivary gland biopsy were included, and those with IgG4-related disease (IgG4-RD) or other confounding factors were excluded. Clinical and laboratory CSS profiles were compared with those of a control group of patients with typical pSS from the Korean Initiative of Primary Sjögren's Syndrome (KISS) prospective cohort study. Twenty-one with CSS and 501 patients with pSS from Seoul St. Mary's Hospital were retrospectively analyzed.

Results

Patients with CSS were older at diagnosis, had a lower prevalence of ocular symptoms, and exhibited distinct immunological markers compared to those with pSS. Logistic regression analysis revealed that anti-Ro antibody positivity, elevated erythrocyte sedimentation rate levels, low serum complement 3 levels, and accompanying dry eye symptoms were factors distinguishing pSS from CSS.

Conclusion

Even after excluding IgG4-RD, CSS was significantly different from pSS in terms of clinical and laboratory findings. Recognition of these differences is crucial for the accurate diagnosis and management of CSS, underscoring its status as a distinct pathological entity among salivary gland pathologies.

Idiopathic hyalinizing fibrosclerosis: A systemic steroid-resistant condition distinct from IgG4-related disease

Since the concept of IgG4-related disease (IgG4-RD) was proposed, that diagnosis has been considered in idiopathic fibroinflammatory diseases in various organs, particularly in cases with multi-organ involvement. We have recently encountered three cases of fibrosing disease of uncertain etiology with shared microscopic appearances. Case 1 (56-year-old man) had an irregular mass at the base of mesentery. Case 2 (29-year-old woman) presented with obstructive jaundice due to an ill-defined mass at the hepatic hilum and two lung nodules. Case 3 (53-year-old man) had multiple solid nodules in the mediastinum, peritoneum, retroperitoneum, and mesentery; he also had diffuse irregular narrowing of the intra- and extra-hepatic bile ducts in keeping with sclerosing cholangitis. Serum IgG4 concentrations were not elevated. Biopsies from the nodular lesions showed extensive hyalinizing fibrosis with an only focal lymphoplasmacytic infiltrate. Thick collagenous bundles are arranged in an irregular or partly whorl pattern. Typical storiform fibrosis or obliterative phlebitis was not observed. The number of IgG4-positive plasma cells was <10 cells/high-power field; the ratio of IgG4/IgG-positive plasma cells was <30%. After the histological diagnosis of sclerosing mesenteritis, pulmonary hyalinizing granuloma, and mediastinal fibrosis was made, they were treated with a trial of steroids, but none showed a significant response. In conclusion, a hyalinizing fibrotic condition can occur at various anatomical sites. They have shared microscopic findings, and are steroid-resistant. Although the clinical presentation may mimic IgG4-RD, the two conditions are likely distinct. We would propose a diagnostic term of 'idiopathic hyalinizing fibrosclerosis' for this under-recognized, rare, systemic condition.

Systemic diseases affecting the GI tract: A review of clinical and histopathologic manifestations

A variety of systemic diseases may affect the gastrointestinal (GI) tract. Since the GI tract responds to injury in limited ways, identifying these processes may be challenging, especially on small endoscopic biopsies. This article reviews the clinicopathologic features of commonly encountered systemic diseases affecting the tubular GI tract: sarcoidosis, graft vs. host disease, mast cell disorders, systemic sclerosis, and IgG-4 related disease. In addition, we offer guidance in differentiating them from their mimics.

Chronic Sclerosing Sialadenitis of the Submandibular Gland and its Histopathological Spectrum in the IgG4-Related Disease: a Series of 17 Cases

PURPOSE

This study aimed to characterize the histopathological immunohistochemical features of chronic sclerosing sialadenitis, emphasizing the IgG4-related disease.

METHODS

Seventeen cases of chronic sclerosing sialoadenitis were examined for histopathological aspects, (inflammation, fibrosis, glandular parenchyma, and lymphoid follicles) and immunohistochemistry (BCL2, CD3, CD20, CD34, CD163, p63, cyclin D1, mast cell, SMA, S100A4, IgG, and IgG4) which were scored. IgG4-related disease features were investigated. Demographic and clinical data were also collected.

RESULTS

Males predominated (10:7), with an average lesion size of 3.9 cm. Common histopathological findings included reduced acinar parenchyma, lymphoid follicle formation, and ductular proliferation. CD3-positive T lymphocytes and CD34- and SMA-positive stromal fibroblasts were abundant. Nine cases (53%) showed sialoliths and three cases met the criteria for IgG4-related disease.

CONCLUSION

CSS of the submandibular gland represents a reactive pattern rather than IgG4-RD as only 3 cases seemed to be related to IgG4-RD. The immunohistochemical profile revealed an abundant population of CD3-positive T lymphocytes, as opposed to regulatory proteins such as cyclin D1, demonstrating that populations of CD34- and SMA-positive stromal fibroblasts contribute to the fibrosis characteristic of CSS. In addition, our results provide a comprehensive insight into the study of CSS and its relationship with IgG4-RD.

Assessment of specificity of dermatopathologic criteria for IgG4-related skin disease

BACKGROUND

IgG4-related disease (IgG4-RD) represents a recently characterized multisystemic fibroinflammatory condition that can manifest a spectrum of skin findings (IgG4-related skin disease; IgG4-RSD). Histopathologic and immunohistochemical criteria have been proposed; however, the specificity of these criteria merits scrutiny given the potential histopathologic overlap of IgG4-RSD and both neoplastic and inflammatory skin conditions featuring lymphoplasmacytic infiltrates (IgG4-RSD mimics). This study sought to assess the specificity of the criteria by quantifying the frequency by which an expanded spectrum of IgG4-RSD mimics meet proposed thresholds.

METHODS

Following IRB approval, a total of 69 cases of IgG4-RD mimics, representing 14 different diagnoses featuring plasma cells, were reviewed and analyzed for the following histopathologic and immunohistochemical features: (i) maximum IgG4+ count/high-powered field (hpf) >200; (ii) IgG4/IgG ratio >0.4 averaged over 3 hpfs; (iii) IgG4+ count >10 per hpf.

RESULTS

Screening for IgG4-RSD by histopathologic criteria demonstrated the high frequency of lymphoplasmacytic infiltrates, contrasted with the rarity of storiform fibrosis (only one case of erythema elevatum diutinum [EED]) and obliterative phlebitis (0 cases). By immunohistochemical criteria, the analysis revealed that no cases exceeded 200 IgG4+ cells; 13% (9/69) cases demonstrated an IgG4/IgG ratio of >0.4 averaged over 3 hpfs; and 23% (16/69) cases demonstrated a mean IgG4+ count of >10 per hpf.

CONCLUSION

Application of proposed IgG4-RSD histopathologic criteria to an expanded spectrum of potential IgG4-RSD mimics (to include cutaneous marginal zone lymphoma, syphilis, necrobiosis lipoidica, lichen sclerosus, ALHE, psoriasis, lymphoplasmacytic plaque, EED, and erosive pustular dermatosis), highlights the relative nonspecificity of lymphoplasmacytic infiltrates contrasted with the stringency of storiform fibrosis and obliterative fibrosis. Furthermore, an IgG4+ cell count of >10 per hpf and an IgG4/IgG ratio of >0.4 are not specific to IgG4-RSD alone. In the appropriate clinical context for IgG4-RSD, histopathologic features still represent the entry threshold for diagnosis consideration, which then allows for further screening by immunohistochemical criteria.

Hepatic Inflammatory Pseudotumor-Focusing on Its Heterogeneity

Hepatic inflammatory pseudotumors (IPTs) are defined as benign, non-malignant, non-metastasizing tumors characterized by the presence of myofibroblastic spindle cells, hetorogenous populations of inflammatory cells, particularly plasma cells, lymphocytes and macrophages, as well as locations of fibrosis and necrosis without cellular anaplasia or atypical mitoses. Despite subsequent reports in the references, hepatic IPT remains difficult to diagnose; while posing major issues specifically for its differential diagnosis compared with that of other various benign diseases and malignant hepatic tumors. Histopathological findings are always a requisite for confirming the diagnosis, particularly given that the pathogenesis of IPT remains ambiguous to date. Hepatic IPT is a heterogeneous entity in terms of its clinical features, pathological findings, and pathogenesis. Once the diagnosis is confirmed, however, needless surgery such as wedge resection and lobectomy should be avoided. Here, we discuss the heterogeneity of hepatic IPT, its clinical features, pathological findings, and pathogenesis, and describe its differential diagnosis.

Immunological characteristics of IgG4-related Kuttner tumors

Immunoglobulin G4-related disease (IgG4-RD) has recently been well recognized and Kuttner tumor is known to be a chronic sclerosing sialadenitis, representing the focal manifestation of IgG4-RD, in the submandibular gland (SMG). This study is to evaluate the immunologic features of IgG4-related Kuttner tumor in the SMG. We retrospectively chose 13 patients who were confirmed as having Kuttner tumor by surgical biopsy between May 2012 and January 2019. The fine-needle aspiration cytology, serum antibody levels (anti-Ro antibodies, anti-La antibodies), IgG serum levels (total IgG and IgG4), and immunohistochemical findings for IgG and IgG4-positive plasma cells were reviewed. The cytologic results found that 7 of the 9 cases were reported as chronic sialoadenitis, and the other 3 as benign lymphoproliferative lesion. The serum levels of autoantibodies, Sjögren-syndrome-related antigen A/Ro-Ab and Sjögren-syndrome-related antigen A/Ro-La, showed all normal values of serum level. The serum level of IgG was increased in only 4 among the cases. However, the IgG4 levels were significantly increased in 11 among the cases. In all the patients who received resection of SMG, immunohistochemical findings showed all positive for IgG4-RD, with elevated numbers of IgG and IgG4-positive plasma cells. The evaluation of IgG4 serum level should be very informative for the diagnosis of this tumor before surgery. Fine-needle aspiration cytology with ultrasound guidance are not conclusive in this study. The immunological study including IgG4 serum level should be required for proper diagnosis and treatment, with clinical features of the Kuttner tumor. The level of evidence was IV.

Clinical and Serological Features in Latin American IgG4-Related Disease Patients Differ According to Sex, Ethnicity, and Clinical Phenotype

BACKGROUND/OBJECTIVE

Data on IgG4-related disease (IgG4-RD) come almost exclusively from cohorts from Asia, Europe, and North America. We conducted this study to describe the clinical presentation, phenotype distribution, and association with sex, ethnicity, and serological markers in a large cohort of Latin American patients with IgG4-RD.

METHODS

We performed a multicenter medical records review study including 184 Latin American IgG4-RD patients. We assigned patients to clinical phenotypes: group 1 (pancreato-hepato-biliary), group 2 (retroperitoneal/aortic), group 3 (head and neck-limited), group 4 (Mikulicz/systemic), and group 5 (undefined). We focused the analysis on how sex, ethnicity, and clinical phenotype may influence the clinical and serological presentation.

RESULTS

The mean age was 50.8 ± 15 years. Men and women were equally affected (52.2% vs 48.8%). Fifty-four patients (29.3%) were assigned to group 1, 21 (11.4%) to group 2, 57 (30.9%) to group 3, 32 (17.4%) to group 4, and 20 (10.8%) to group 5. Male sex was associated with biliary tract (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.36-8.26), kidney (OR, 3.4; 95% CI, 1.28-9.25), and retroperitoneal involvement (OR, 5.3; 95% CI, 1.45-20). Amerindian patients presented more frequently with atopy history and gallbladder involvement. Group 3 had a female predominance.

CONCLUSIONS

Latin American patients with IgG4-RD were younger, and men and women were equally affected compared with White and Asian cohorts. They belonged more commonly to group 1 and group 3. Retroperitoneal and aortic involvement was infrequent. Clinical and serological features differed according to sex, ethnicity, and clinical phenotype.

Synchronous but separate neuroendocrine tumor and high-grade dysplasia/adenoma of the gall bladder: A case report

BACKGROUND

Gall bladder neuroendocrine tumors (GB-NETs) are rare, accounting for less than 0.5% of all NETs. They usually lack specific symptoms and are difficult to diagnose preoperatively. In most cases, GB-NETs are incidentally found after cholecystectomy for large polyps or cholelithiasis, causing acute or chronic cholecystitis. The coexistence of GB-NET and GB adenocarcinoma is very rare.

CASE SUMMARY

We report a case of synchronous but separate GB-NET and adenoma with high-grade dysplasia in a patient who had undergone surgery for a progressively growing GB polypoid lesion. To the best of our knowledge, simultaneous separation of NETs and cancer in the GB has not been reported.

CONCLUSION

Coexistent GB carcinoid tumor and adenocarcinoma is rare. A surveillance program is needed for these large GB polyps.

Chronic sclerosing sialadenitis (Küttner's tumour) of the submandibular gland: a neoplastic mimic

A 74-year-old man was referred for a plastic surgery consultation for two previous acute episodes of right submandibular sialadenitis. Physical examination revealed a lump in the right submandibular region, painful on palpation. The initial impression on clinical examination was of sialolithiasis. The sonography demonstrated a structural heterogeneity of the submandibular gland with a hypoechogenic and vascularised nodular formation (1.5×1.2 cm), suggestive of a mixed tumour of the right maxillary gland, requiring histological evaluation. He underwent a right submandibulectomy and an IgG4-positive chronic sclerosing sialadenitis was diagnosed. The patient's condition evolved favourably, resulting in a full recovery. The clinical features and differential diagnosis of this entity are debated in light of relevant literature.

IgG4-positive plasma cells in nonspecific sialadenitis and sialolithiasis

Chronic sclerosing sialadenitis is commonly regarded as a manifestation of IgG4-related disease. We previously found that a high IgG4 expression or IgG4-related disease could accompany nonspecific sialadenitis, whereas chronic sclerosing sialadenitis was not directly associated with IgG4-related disease. Our previous findings lead us to hypothesize that these inflammatory conditions of the submandibular gland signify a continuous progression of disease rather than different disease entities. We, therefore, aimed to determine the presence of IgG4-positivity and genuine IgG4-related disease in a cohort of 165 submandibular gland specimens from patients who underwent surgery due to chronic nonspecific sialadenitis or sialolithiasis. To do so, we re-evaluated histopathological features and divided samples into three groups: (A) nonspecific sialadenitis without known sialolithiasis, (B) sialadenitis with sialolithiasis, and (C) sialolithiasis without sialadenitis. We performed immunohistochemical staining for IgG4, IgG, and CD31, and assessed the Boston consensus statement criteria for IgG4-related disease in IgG4-positive samples. We also reviewed patient records and supplemented follow-up data with a questionnaire among patients with IgG4-positive samples. IgG4-positive plasma cells (range 1-344) were found in 131 samples. Among these, 19 samples were classified as IgG4-positive (≥70 IgG4-positive plasma cells/high-power field). Two IgG4-positive samples were histologically highly suggestive of IgG4-related disease, but only one had a clinically confirmed diagnosis of IgG4-related disease. Our results indicate that patients with sialadenitis and sialolithiasis often present with IgG4-positive lymphoplasmacytic infiltrates, but exceedingly rarely present with genuine IgG4-related disease. In sialolithiasis without sialadenitis, IgG4-positive plasma cells are often absent or appear in small numbers. These results support our hypothesis of a continuum of disease, and indicate that progressive inflammation of the submandibular gland leads to the development of more specific pathological features over time.

Histological features of autoimmune pancreatitis and IgG4-related sclerosing cholangitis with a correlation with imaging findings

Autoimmune pancreatitis (AIP) is characterized by a tumefactive inflammatory lesion resembling pancreatic carcinoma. Type 1 AIP is a pancreatic manifestation of IgG4-related disease characterized by unique histological features that can be identified on imaging. The capsule-like rim, which is a collar of hypertrophic lesion surrounding the pancreas, consists of lymphoplasmacytic infiltration and fibrosis, and storiform fibrosis is often identified. Hypertrophic lesions of various microscopic architectures such as the ducts, veins (obliterative phlebitis), arteries (periarteritis), and nerves are observed without parenchymal damage. The pancreatic lobules keep their contours, but the acinar cells are diminished and replaced by numerous inflammatory cells. These features provide clues to arrive at a diagnosis of type 1 AIP and to distinguish it from pancreatic carcinoma on imaging. In contrast, type 2 AIP is an epithelium-centered inflammation involving the ducts and lobules. Neutrophilic infiltration in the epithelium and/or lumens (granulocytic epithelial lesion) is a characteristic finding. Lobular swelling due to inflammation is the cause of pancreatic enlargement. IgG4-related sclerosing cholangitis is histologically similar to the hypertrophic ductal lesion in type 1 AIP and characterized by wall thickening due to inflammation and luminal stenosis. The epithelium is intact, which is different from bile duct carcinomas and primary sclerosing cholangitis, the latter of which is characterized by inflammation targeting the epithelium. Although the histological features of type 1 AIP and IgG4-related sclerosing cholangitis are unique, the biopsy diagnosis of these diseases has limitations, which should be recognized by clinicians.

Ultrasonography of IgG4-related dacryoadenitis and sialadenitis: Imaging features and clinical usefulness

OBJECTIVES

To clarify the ultrasonographic features of immunoglobulin G4 (IgG4)-related dacryoadenitis and sialadenitis (IgG4-DS) and their usefulness in clinical diagnostic sessions.

METHODS

By re-evaluating 96 consecutive patients with IgG4-related disease, we identified 54 patients (male:female = 37:17; median age, 69.5 years) who underwent lacrimal or submandibular gland (LG or SG, respectively) ultrasonography and computed tomography (CT). Their clinical and ultrasonographic features were retrospectively analysed. Radio-pathological correlations were also examined in LG (23 cases) and SG lesions (20 cases). Additionally, the diagnostic accuracy of CT for LG/SG lesions was evaluated.

RESULTS

Abnormal ultrasonographic findings were detected in 33 (LGs) and 38 (SGs) patients, and most of them were observed bilaterally. All lesions were well demarcated and demonstrated diffuse low-echoic areas (rocky pattern) or multiple low-echoic nodules surrounded by high-echoic linear shadows (cobblestone pattern) corresponding to intra-lobular inflammation and inter-lobular fibrosis. Moreover, 42% (LGs; 14/33) and 42% (SGs; 16/38) patients had glandular lesions without clinical symptoms associated with the affected glands. The diagnostic accuracy of CT was ∼80% for LG and 55% for SG.

CONCLUSIONS

Ultrasonographic findings in IgG4-DS included diffuse or nodular low-echoic areas with linear high-echoic structures corresponding to inflamed lobules and inter-lobular fibrosis. These findings can help detect IgG4-DS.

Olfactory dysfunction in LATY136F knock-in mice

OBJECTIVE

This study examined olfactory dysfunction in LATY136F knock-in mice and its pathogenic mechanism.

METHODS

The olfactory function of LATY136F knock-in mice was assessed by a behavioral test using cycloheximide solution, which has been used as a mice repellant because of its peculiar smell and unpleasant taste. The tests were administered to each group of LATY136F knock-in mice and WT mice at 8, 12, 16, 20, and 24 weeks of age. After the behavioral tests to evaluate olfactory function, the mice were sacrificed for evaluations by immunohistochemistry.

RESULTS

Behavioral tests to evaluate olfactory function showed that the LATY136F knock-in mice had a statistically significant level of olfactory dysfunction (P < 0.05). Histological analysis showed that the thickness of the olfactory epithelium in these mice was thinner than that in the age-matched wild type mice. There was no IgG4-RD like lesion in the olfactory epithelium of LATY136F knock-in mice. Olfactory marker protein and growth-associated protein 43 expressions in the olfactory epithelium of the LATY136F knock-in mice were markedly lesser than those in the wild type mice (P < 0.05).

CONCLUSION

The present study demonstrated that olfactory disturbances occurred in LATY136F knock-in mice. Furthermore, the mechanism was suggested to be reduced regeneration of the olfactory epithelium.

Involvement of two or more sets of lacrimal glands and/or major salivary glands is related to greater systemic disease activity due to multi-organ involvement in IgG4-related dacryoadenitis/sialadenitis

OBJECTIVES

In IgG4-related dacryoadenitis and/or sialadenitis (IgG4-DS), involvement of two or more sets of lacrimal glands (LGs) and/or major salivary glands (MSGs) is regarded as a specific finding with diagnostic significance. This study aimed to clarify the influence of this factor on the overall clinical picture of IgG4-DS.

METHODS

We retrospectively reviewed the medical records of 130 patients with IgG4-related disease, 97 of whom were diagnosed with IgG4-DS. We determined their clinical features according to the presence/absence of involvement of ≥2 sets of LGs and/or MSGs and compared the results with those obtained in 33 DS-limited patients.

RESULTS

The IgG4-DS patients comprised 60 men and 37 women (median age 65 years). The median serum IgG4 level at diagnosis was 548 mg/dL. The patients with involvement of ≥2 sets (n = 44) had significantly more affected organs, lower serum C3 and C4 levels, and a tendency to have higher serum IgG levels and IgG4-RD responder index than did those without it (n = 53). In the 33 DS-limited patients, these two groups had no significant differences in clinical features.

CONCLUSIONS

Involvement of ≥2 sets of LGs and/or MSGs suggests greater systemic disease activity mainly reflected by involvement of more organs.

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.

Imaging of IgG4-related disease in the extracranial head and neck

PURPOSE

Immunoglobulin G4-related disease (IgG4-RD) is a newly defined fibro-inflammatory multisystemic condition defined by a triad of diagnostic criteria based on clinical presentation, biochemical and histopathological findings. Whereas some subsites of this disease have been well described in the literature so far (e.g. pancreas, kidneys, retroperitoneum, salivary glands), more recently identified anatomical sites of involvement in the head and neck are less well understood (e.g. nose, paranasal sinuses).

METHOD

This pictorial review details the imaging appearances of extracranial IgG4-RD in the Head & Neck. Multimodality imaging appearance and features are presented, with reference to the published literature to date.

RESULTS

Following a subsite-based approach, we present both the most common and the more rarely encountered imaging patterns of IgG4-RD in the extracranial head and neck, along with the relevant differential diagnoses to consider. Our institutional experience not only cements what is already known in the existing literature on this topic, but also reveals new imaging features of IgG4-RD, notably in the sinonasal tract.

CONCLUSIONS

This pictorial review of extracranial head & neck IgG4-RD will enable radiologists to recognise the features of this condition and propose it as a differential diagnosis to include alongside other probable entities. It establishes the place of the radiologist in the diagnosis and management of IgG4-RD.

Not All Küttner Tumors Are IgG4-Related Disease (IgG4-RD)

Küttner tumor is an uncommon cause of salivary gland enlargement that most frequently affects the submandibular gland. More recently it has been considered a manifestation of IgG4-related disease (IgG4-RD) and synonymous with chronic sclerosing sialadenitis (CSS). We present a series of cases to emphasize this clinical entity as a disease pattern and presentation that is separate from IgG4-RD. Retrospective case series of 3 patients with unilateral salivary gland enlargement, or "Küttner tumor," histologically classified as "chronic sclerosing sialadenitis," The clinical history, radiology reports, laboratory studies, and pathology slides were reviewed for each case. Radiology showed discrete unilateral mass-like lesions in all three cases. Immunohistochemistry showed reduced tissue IgG4-positive plasma cells in two cases and increased numbers in one case, but insufficient to diagnose IgG4-RD. Storiform fibrosis was not seen in all cases and did not coincide with increased IgG4-positive plasma cells. A systemic workup, including serum IgG4 levels in two cases, was normal. A brief review of the literature on the spectrum of salivary gland involvement by IgG4-RD is presented. Küttner tumor is not necessarily the same as chronic sclerosing sialadenitis and is not always associated with IgG4-related disease. This report includes the second documented case of Küttner tumor of the sublingual gland.

IgG4-Related Disease of the Ovary

Immunoglobulin G4-related disease is characterized by dense fibrosis, obliterative phlebitis, and lymphoplasmacytic infiltration that contains abundant IgG4 positive plasma cells. It causes tumefactive lesions in the involved organs and is most commonly seen in the salivary glands, pancreas, and retroperitoneum. Ovarian involvement has been reported in only two cases. In our case, a 58-year-old female patient presented with abdominal distention and pain. Pelvic computed tomography revealed a soft tissue lesion compatible with the omental cake, several intraabdominal implants, and bilateral adnexal fullness. A laparotomy was performed under suspicion of peritoneal carcinomatosis secondary to bilateral adnexal mass. In the histopathologic examination, abundant lymphoplasmacytic infiltration and dense fibrosis were observed in both ovaries and the peritoneum. In the areas of greatest density, the density of IgG4-positive plasma cells was found to range from 40 to 50 per high-power field. The patient was accepted as suffering from probable IgG4-related disease because of the bilateral involvement of the ovaries and the histopathological findings. In conclusion, we present this case to draw attention to the fact that IgG4-related disease can also be seen in the ovary.

IgG4-related disease: Changing epidemiology and new thoughts on a multisystem disease

IgG4-related disease (IgG4-RD) represents an immune-mediated fibroinflammatory condition with peculiar histopathologic changes that can affect various organs. In 2012 its unified nomenclature was published, which allows to abandon other synonymous names. Up to now, only little is known about its epidemiology around the world. However, although it is generally considered a rare condition, the number of patients with IgG4-RD is increasing enormously. Likewise, the annual number of publications on this subject has increased progressively. The spectrum of clinical manifestations in IgG4-RD is highly variable, depending on the severity of the disease as well as the presence of organ(s) involvement. This review gives an overview on changing epidemiology of IgG4-RD focusing the attention on the large cohorts of patients published in the literature.

Application of Lip Biopsy for the Histological Diagnosis of Immunoglobulin G4-Related Disease

We describe the case of a 51-year-old woman with immunoglobulin G4-related disease (IgG4-RD) diagnosed using lip biopsy. She reported having bilateral submandibular nodules for a month. Magnetic resonance imaging showed diffuse swelling in the bilateral submandibular glands (SMGs), suggesting inflammatory changes. Laboratory data revealed an elevated level of serum IgG4. Fine needle aspiration cytology of the SMG showed a considerable number of lymphocytes with degeneration but did not demonstrate specific findings for a definitive diagnosis of IgG4-RD. Lip biopsy was performed, and a biopsy specimen from the labial salivary gland showed abundant lymphoplasmacytic infiltration with a large number of IgG4-positive cells. The patient was diagnosed with IgG4-RD based on histological and laboratory findings. Findings of further examinations revealed that the patient had autoimmune pancreatitis, confirming our diagnosis. Four months after prednisolone administration, improvement of the submandibular and pancreatic lesions was observed. One year after the initial presentation, the serum IgG4 level was normalized. In cases of IgG4-RD with salivary gland involvement, lip biopsy might be one of the options for the histological diagnosis of IgG4-RD.

IgG4-related disease: a contemporary review

Background/aim

Immunoglobulin G4-related disease (IgG4-RD), is an immune-mediated fibroinflammatory condition, which may involve multiple organs and mostly presents with high serum IgG4 levels and specific histopathological characteristics. As IgG4-RD is a relatively new entity the etiology, prevalence and epidemiologic knowledge is quite limited. Although involvement of almost all anatomical regions has been reported, the most commonly affected regions are pancreas, lacrimal glands, salivary glands, retroperitoneum, orbita, lymph nodes, kidney and lungs. Diagnosis is made with combined evaluation of clinical, radiological and histopathological findings. Typical histopathological features include storiform fibrosis, dense lymphoplasmacytic infiltrates and obliterative phlebitis. Its course is typically marked by remission and relapsing attacks and it may lead to fibrosis, destructive lesions in tissues and organ failure unless promptly treated. In the treatment of IgG4-RD, many approaches including surgical resection of tissues, systemic glucocorticoids, steroid-sparing immunosuppressive drugs, and biological agents are employed. Although association is not clear, malignancies are frequently reported in IgG4-RD patients. Therefore, it is prudent to monitor patients for the symptoms of malignant diseases.

Conclusion

In this review, recent advances in clinico-pathological characteristics, diagnosis, and treatment of IgG4–RD are discussed.

IgG4-related Disease with a Cardiac Mass

A 69-year-old man with palpitations and decreased blood pressure was referred. Echocardiography showed a mass in the right atrium and cardiac septum. The serum IgG4 level was 1,450 mg/dL. A biopsy of the cardiac mass showed fibrosis with inflammatory cells and increased IgG4-positive plasma cells and lymphocytes. Flow cytometry and polymerase chain reaction of the immunoglobulin heavy chain did not demonstrate monoclonality. He was diagnosed with IgG4-related disease (IgG4-RD). IgG4-RD with a cardiac mass is rare and it is difficult to distinguish it from malignant lymphoma by a pathological examination alone. We therefore performed a biopsy and analyzed the clonality in order to make an accurate diagnosis of 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.

Sclerosing sialadenitis of the submandibular gland is rarely an immunoglobulin G4-related disease in the Finnish population

Chronic sclerosing sialadenitis may represent one of many manifestations of an immunoglobulin G4-related disease. However, existing studies typically consist of small patient cohorts rarely conducted in Western populations. The clinical behavior of chronic sclerosing sialadenitis, including follow-up data, warrants further study. Thus, we aimed to determine whether chronic sclerosing sialadenitis always presents as IgG4-related disease or associates with autoimmune diseases and to determine which additional examinations patients may require. Between 2000 and 2017, 51 patients undergoing submandibular gland resection within the Helsinki University Hospital area were diagnosed with chronic sclerosing sialadenitis. We re-evaluated all specimens and performed immunostaining for IgG4. IgG and CD31 stainings were performed for IgG4-positive specimens. IgG4-related disease diagnosis was defined by the Boston consensus statement criteria. We revised clinical data, distributing a follow-up questionnaire to patients to register symptoms of IgG4-related disease or autoimmune disease during follow-up. The chronic sclerosing sialadenitis criteria were fulfilled in 34 patients, whereby 17 were diagnosed as non-sclerosing chronic sialadenitis. In 19 cases, a sialolith associated with a salivary gland lesion. In total, 12 of 51 cases were recognized as IgG4-positive, while two met the criteria for IgG4-related disease. These two cases belonged to the non-sclerosing chronic sialadenitis group, and both involved other organs. The histopathological features between chronic sclerosing sialadenitis and non-sclerosing chronic sialadenitis overlapped regarding the degree of fibrosis and inflammatory infiltrates. In the Finnish population, chronic sclerosing sialadenitis of the submandibular gland does not appear to present as IgG4-related disease. Non-sclerosing chronic sialadenitis can associate with IgG4-related disease. A histopathological distinction between chronic sclerosing sialadenitis and non-sclerosing chronic sialadenitis is not always unequivocal and the presence of a sialolith does not exclude IgG4-positivity. Therefore, immunostaining for IgG4 should be performed when dense plasma cell infiltration is present in either non-sclerosing chronic sialadenitis or chronic sclerosing sialadenitis.

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.

IgG4-related disease presenting as otogenic skull base osteomyelitis

IgG4-related disease (IgG4-RD) is an emerging clinical disease entity characterized by tumefactive lesions at multiple sites with a dense lymphoplasmacytic infiltrate rich in IgG4+ plasma cells. Although almost any organ can be affected, IgG4-RD is most likely to involve the submandibular, lacrimal, or parotid glands in the head and neck region. However, skull base involvement presenting as otogenic skull base osteomyelitis (SBO) is rare. We encountered a 70-year-old male with IgG4-RD presenting primarily with severe otalgia and otorrhea. He had uncontrolled diabetes mellitus and showed clinical manifestations of otogenic SBO. Tissue immunostaining revealed typical features of increased IgG4-positive plasma cells, and hematological examination showed elevated serum IgG4 concentrations. Treatment with corticosteroids significantly improved well-being and partially resolved the lesion based on computed tomography (CT) scan.

FDG PET/CT in Isolated Mediastinal Immunoglobulin G4-Related Disease

Immunoglobulin G4-related disease is a fibroinflammatory condition that has the tendency to involve almost every organ of the body. We report the case of a young asymptomatic man with right suprahilar opacity on chest radiograph detected during routine annual health check-up. Mediastinoscopic sampling of the lesion was inconclusive. F-FDG PET/CT done to characterize the lesion revealed hypermetabolic mass with areas of necrosis in the right paratracheal location. Histopathologic examination from the FDG PET/CT-guided biopsy sample was suggestive of immunoglobulin G4-related disease.

Acute Tubulointerstitial Nephritis as a Sole Manifestation of Immunoglobulin G4-Related Disease

This is a case report of a patient who developed severe acute kidney disease with kidney biopsy showing interstitial nephritis, plasma cell infiltration and immunoglobulin G4 (IgG4) expression consistent with IgG4-related kidney disease. There were no other systemic features of IgG4-related disease. The patient was treated with corticosteroids and mycophenolate. This case highlights the need to consider IgG4-related kidney disease even in the absence of other systemic features. Isolated renal involvement is underrecognized and can lead to missed diagnosis. It also illustrates that mycophenolate can be used as a steroid sparing agent in this condition; an observation that adds to the limited literature in this field.

Tumefactive Inflammatory Diseases of the Pancreas

Advances in the past two decades have resulted in the recognition of several tumefactive pancreatic lesions that, on histologic evaluation, show a varying combination of inflammation and fibrosis. Autoimmune pancreatitis, the prototypic tumefactive pancreatic fibroinflammatory lesion, is composed of two distinct diseases, type 1 autoimmune pancreatitis and the less common type 2 autoimmune pancreatitis. Although designated as autoimmune pancreatitis, the two diseases show little morphologic or pathogenic overlap. In type 1 disease, subsets of T lymphocytes (type 2 helper T cells, regulatory T cells, and T follicular helper 2 cells) are hypothesized to drive the inflammatory reaction. The B-cell response is characterized by an oligoclonal expansion of plasmablasts, with dominant clones that vary among patients and distinct clones that emerge at the time of relapse. Although the precise role of IgG4 in this condition remains uncertain, recent studies suggest that other IgG subclasses (eg, IgG1) may mediate the immune reactions, whereas IgG4 represents a response to dampen excessive inflammation. A recent study of type 2 autoimmune pancreatitis highlights the role of CXCL8 (alias IL-8), with duct epithelium and infiltrating T lymphocytes expressing this chemokine; the latter may contribute to the distinct form of neutrophilic inflammation in this disease. The review also highlights other forms of mass-forming chronic pancreatitis: follicular pancreatitis, groove pancreatitis, and those associated with rheumatologic diseases.

An unusual presentation of chronic sclerosing sialadenitis of submandibular gland (Kuttner's tumour)

Kuttner's tumour, also known as chronic sclerosing sialadenitis, is a localised form of IgG4 disease which presents as asymptomatic submandibular gland swelling. The diagnosis is usually based on histopathology and immunohistochemistry. A 33-year-old woman presented with acute-onset pain and swelling in the right submandibular region. Clinical examination showed an enlarged submandibular gland, and CT showed a calculus in the Wharton's duct. After treating the acute phase with antibiotics, the patient underwent submandibular gland excision and calculus removal. Histopathology of the specimen showed areas of periductal sclerosis, acinar atrophy and intense lymphoplasmacytic infiltrates with occasional eosinophils. The IgG4 to IgG plasma cell ratio was >40%, suggestive of an IgG4-related disease. The authors have chosen to report this case because of the unusual presentation of IgG4 disease as acute sialadenitis.

Chronic sclerosing sialadenitis (Küttner's tumor) of the submandibular salivary gland: Our experience of one case report

Surgical excision of the submandibular salivary gland in patients with chronic sclerosing sialadenitis can be complicated because of hyalinosis of the surrounding soft tissues. Patients with autoimmune diseases suspected of having salivary gland neoplasms or granulomatous disease should be carefully investigated for chronic sclerosing sialadenitis to prevent potential harm.

Immunoglobulin G4-related disease complicated with vascular lesions: CT findings in 21 patients

PURPOSE

We aimed to analyze multislice computed tomography (MSCT) imaging features of vasculitis in immunoglobulin G4-related disease (IgG4-RD).

METHODS

In this retrospective study, we diagnosed 21 definite or possible IgG4-RD patients (71.4% male; mean age, 52.1±4.5 years) with vasculitis by MSCT and pathologic examination. The clinical background, laboratory analysis, pathologic results, CT images, and response to therapy were assessed and analyzed.

RESULTS

Under enhanced MSCT, 50 vasculitic lesions were identified and were divided into five types (types A-E) according to the CT findings on the basis of luminal changes. There were more vasculitic lesions observed below the diaphragm (n=30) than above it (n=20). Aneurysms and aneurysmal dilatation were more likely to be found in the aortaventralis (n=5), aortic arch (n=3) and iliac arteries (n=3). Most of the vascular lesions were characterized by wall thickening with a normal lumen (n=15) and slight stenosis (n=22). The affected vascular walls were all thickened between 4 and 18 mm. The walls of 19 patients (90.4%) were well circumscribed. The wall thickness of the aorta, including the aortaventralis and aortic arch, was more notable than that of the other vascular sites. Fourteen patients were followed up for 2-24 months. Wall thickness decreased in all cases. The average maximum thicknesses before and after therapy were 12.2±2.7 mm and 6.1±1.8 mm, which were significantly different (P < 0.001). The lumens of two patients were found to be slightly enlarged, while those of the other cases were unchanged after therapy.

CONCLUSION

IgG4-RD vascular lesions can be divided into five types, which are more likely to be present in the aorta and its main branches, and can rapidly diminish after steroid therapy. The lumen may be unchanged or slightly enlarged.

Dental-craniofacial manifestation and treatment of rare diseases

Rare diseases are usually genetic, chronic and incurable disorders with a relatively low incidence. Developments in the diagnosis and management of rare diseases have been relatively slow due to a lack of sufficient profit motivation and market to attract research by companies. However, due to the attention of government and society as well as economic development, rare diseases have been gradually become an increasing concern. As several dental-craniofacial manifestations are associated with rare diseases, we summarize them in this study to help dentists and oral maxillofacial surgeons provide an early diagnosis and subsequent management for patients with these rare diseases.

IgG4-related disease: review of the histopathologic features, differential diagnosis, and therapeutic approach

Immunoglobulin G4-related disease (IgG4-RD) is an uncommon disorder that demonstrates characteristic clinicopathologic features including sclerosing lesions with storiform fibrosis, increased IgG4+ plasma cells with an increased IgG4+/IgG+ plasma cell ratio, obliterative phlebitis, and often an increased serum IgG4 level. This review summarizes the characteristic histopathologic and clinical features of IgG4-RD with detailed discussion of the histopathologic characteristics of the most commonly involved anatomic sites. We also present recent advances in our understanding of the pathophysiologic mechanisms of IgG4-RD and discuss updates on the treatment, prognosis, and outcomes of this rare disease, including discussion of the possible association between IgG4-RD and malignancy.

Sialendoscopic management of autoimmune sialadenitis: a review of literature

Autoimmune diseases of major salivary glands include Sjögren's syndrome and a complex of disorders classified as immunoglobulin G4-related diseases. These pathologies are characterised by an autoimmune reaction mediated by T-helper lymphocytes that targets the ducts of exocrine glands in Sjögren's syndrome and glandular parenchyma in immunoglobulin G4-related diseases. Immunoglobulin G4-related diseases represent recently introduced multi-organ diseases that also involve the salivary glands. However, the morbid conditions once known as Mikulicz's disease and Kuttner's tumour were recently considered as two variants of immunoglobulin G4-related diseases affecting the major salivary glands ( immunoglobulin G4-related sialadenitis). This review briefly summarises the pathogenesis and clinical features of autoimmune diseases of the major salivary glands, focusing on the diagnostic and therapeutic role of sialendoscopy.

IgG4-related Disease - A Systemic Disease that Deserves Attention Regardless of One's Subspecialty

IgG4-related disease (IgG4-RD) is an inflammatory condition characterized by a high serum IgG4 concentration and the abundant infiltration of lymphocytes and IgG4-positive plasma cells in the tissue, as well as spatial (diverse clinical manifestations) and temporal (the possibility of recurrence) multiplicities. Since the initial documentation of IgG4-related disease in patients with autoimmune pancreatitis in 2001, a growing body of evidence has been accumulating to suggest that various-virtually all-organs can be affected by IgG4-RD. In general, steroid therapy is effective and is considered to be the first-line treatment for IgG4-RD. The precise mechanism underlying this systemic disorder has remained unknown. Considering that IgG4-RD was specified as being an intractable disease in 2015, further studies are needed to clarify whether IgG4-RD is indeed a distinct disease entity or a complex of disorders of different etiologies and clinical conditions.

Early Detection and Intervention of Coronary Artery Involvement in Immunoglobulin G4-related Disease

A 59-year-old man with swollen submandibular glands developed an aortic aneurysm requiring aortic prosthesis implantation. Echocardiography performed to evaluate the cardiac function before the surgery incidentally revealed masses around the coronary arteries. The serum IgG4 levels were increased. A post-operational pathological examination of the abdominal aneurysms revealed infiltration of plasma cells, with the ratio of IgG4/IgG-positive cells being >80%. The patient was diagnosed with IgG4-related disease (RD) with coronary artery involvement. He was treated successfully with corticosteroid before any associated cardiovascular events occurred. Given the poor prognosis of IgG4-RD-associated coronary artery involvement, this case emphasizes the importance of the early assessment with echocardiography, even if patients have no cardiovascular symptoms.

Immunoglobulin G4-related ophthalmic disease

Immunoglobulin G4-related disease (IgG4-RD) is a recently recognized inflammatory disease of unknown etiology. It characterized by distinctive histopathological appearance of dense IgG4-positive lymphoplasmacytic infiltrates, storiform fibrosis, and obliterative phlebitis in one or more organs, simultaneously or subsequently. In cases of ocular adnexal involvement, unique clinicohistopathological features were delineated by recent studies, and IgG4-related ophthalmic disease (IgG4-ROD) is generally recognized as the disease name. A significant proportion of previous labeled idiopathic orbital inflammations and Mikulicz's disease are now consistent with a diagnosis of IgG4-ROD. Increasing studies have accumulated regarding its epidemiology, diagnosis, clinical features, treatment, and the association between lymphoma. In this review, we summarize our present understanding of IgG4-ROD.

Current approach to the diagnosis of IgG4-related disease - Combination of comprehensive diagnostic and organ-specific criteria

IgG4-related disease (IgG4-RD) is a fascinating clinical entity proposed by Japanese investigators, and includes a wide variety of diseases, formerly diagnosed as Mikulicz's disease (MD), autoimmune pancreatitis (AIP), interstitial nephritis, prostatitis, retroperitoneal fibrosis, etc. Although all clinicians in every field of medicine may encounter this new disease, a unifying diagnostic criterion has not been established. In 2011, the Japanese IgG4 team, organized by the Ministry of Health, Labor and Welfare (MHLW) of Japan, published comprehensive diagnostic criteria for IgG4-RD. Several problems with these criteria have arisen in clinical practice, however, including the difficulty obtaining biopsy samples from some patients, and the sensitivity and the specificity of techniques used to measure serum IgG4 concentrations. Although serum IgG4 concentration is an important clinical marker for IgG4-RD, its diagnostic utility in differentiating IgG4-RD from other diseases, called IgG4-RD mimickers, remains unclear. This review describes the current optimal approach for the diagnosis of IgG4-RD, based on both comprehensive and organ-specific diagnostic criteria, in patients with diseases such as IgG4-related pancreatitis (AIP), sclerosing cholangitis, and renal, lung and orbital diseases.

IgG4-related cerebral pseudotumor with perineural spreading along branches of the trigeminal nerves causing compressive optic neuropathy: A case report

RATIONALE

Immunoglobulin G4-related disease (IgG4-RD) is characterized by tumor-like lesions, a dense lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells, storiform fibrosis, and obliterative phlebitis. IgG4-RD has been described in a variety of organ systems; however, it rarely involves the central nervous system.

PATIENT CONCERNS

A 17-year-old woman visited our clinic with a complaint of blurred vision for the past 5 months. She also reported a painless right submandibular mass that had been present for 1 year. Her best-corrected visual acuity (BCVA) was 2.0 LogMAR, with an almost total visual field defect in the right eye.

DIAGNOSES

Magnetic resonance imaging (MRI) revealed lobulated parasellar tumors with perineural spreading along branches of the trigeminal nerves causing right optic nerve compression. A craniotomy with tumor removal and submandibular gland biopsy was performed. Histopathological analysis of the tumor revealed stromal fibrosis with atypical lymphoid infiltrations. Histopathological and immunohistochemical analysis of the submandibular gland confirmed the diagnosis of IgG4-RD.

INTERVENTIONS

The patient was administered 500mg/d of pulse methylprednisolone for 3 days, 500mg of intravenous rituximab every 2 weeks (for a total of 2 doses), and 500mg of intravenous pulse cyclophosphamide every month (for a total of 3 doses).

OUTCOMES

Two months after the initiation of immunosuppressive therapy, the patient's BCVA returned to 0.1 LogMAR with visual field defect recovery. The follow-up MRI showed the almost complete disappearance of the previously contrast-enhanced lesions.

LESSONS

Herein, we report a rare case of IgG4-RD presenting as a parasellar tumor and present a review of the related literature. Based on the case report, we propose that aggressive therapy with glucocorticoid, rituximab, and cyclophosphamide may potentially be useful for treating such cases.

Diagnostic sensitivity of cutoff values of IgG4-positive plasma cell number and IgG4-positive/CD138-positive cell ratio in typical multiple lesions of patients with IgG4-related disease

OBJECTIVES

This study aimed to investigate the diagnostic sensitivity of the cutoff values of IgG4-positive plasma cell (PC) number and IgG4-positive/CD138-positive cell ratio proposed by the International consensus statement (ICS) on the pathology of IgG4-related disease (IgG4-RD) in typical multiple lesions of patients with IgG4-RD.

METHODS

We evaluated IgG4-positive PC number and IgG4-positive/CD138-positive cell ratio in 39 samples from 18 IgG4-RD patients having more than two typical lesions of IgG4-RD.

RESULTS

We evaluated 12 submandibular, 12 ophthalmic, six skin, five kidney, two pancreatic, and one bronchus and prostate lesion each in 18 patients with typical clinical, serological, and radiographic features. Concerning IgG4 + PC number per high-power field, most ophthalmic (11/12), kidney (5/5), pancreatic (2/2), and bronchial lesions (1/1) fulfilled the cutoff value of ICS, whereas many of the submandibular (6/12) and skin lesions (0/6) did not. In contrast to the absolute number, all lesions fulfilled the cutoff value of IgG4+/CD138 + cell ratio. In eight cases, only one or two lesions in the same patient fulfilled the cutoff value of ICS, while the others did not.

CONCLUSIONS

These results suggest that ICS criteria have different sensitivities among the affected organs for the diagnosis of IgG4-RD.

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.

A Solid Pseudopapillary Neoplasm of the Pancreas Associated With IgG4-Related Pancreatitis: A Case Report

A solid and cystic pancreatic lesion was incidentally found in a 62-year-old woman on abdominal computed tomography. The lesion was diagnosed as a solid pseudopapillary neoplasm by using endoscopic ultrasound-guided fine needle aspiration, and the tumor was resected. Histologically, the tumor cells had relatively small, round nuclei and papillary-like architecture in a hemorrhagic background. On immunohistochemical examination, the tumor cells were diffusely positive for nuclear β-catenin and cytoplasmic CD10. In addition, typical histological findings of IgG4-related pancreatitis (obstructive phlebitis, storiform-type fibrosis, and abundant IgG4-positive plasma cell infiltration) were found in the surrounding stroma of the solid pseudopapillary neoplasm. Postoperative workup failed to detect any other sclerotic lesions or serum IgG4 elevation, suggesting that the patient had no evidence of IgG4-related disease. To avoid misdiagnosis of a combined pancreatic neoplasm and fibro-inflammatory lesion, pathologists should consider such situations and make a definitive diagnosis after careful observation of all pancreatic lesions.