Cutaneous multicentric Castleman's disease mimicking IgG4-related disease

High serum IgA levels in patients with IgG4-related disease are associated with mild inflammation, sufficient disease-specific features, and favourable responses to treatments

OBJECTIVES

Although elevated serum immunoglobulin A (IgA) levels are thought to exclude a diagnosis of IgG4-related disease (IgG4-RD), IgG4-RD has been definitively diagnosed in some patients despite elevated serum IgA levels. This study aimed to clarify the prevalence of elevated IgA levels in patients with IgG4-RD and to compare the clinical features of IgG4-RD patients with and without elevated IgA levels.

METHODS

The clinical features of 169 IgG4-RD patients were retrospectively compared among those with and without elevated serum IgA levels.

RESULTS

Of the 169 patients with IgG4-RD, 17 (10.1%) had elevated serum IgA levels. Those with elevated serum IgA levels showed higher serum C-reactive protein levels and lower prevalence of relapse than those without. Other clinical features did not differ significantly, including inclusion scores of the American College of Rheumatology/European League Against Rheumatism classification criteria. Cox regression analysis showed that elevated serum IgA levels were associated with a lower incidence of relapse. Moreover, patients with elevated serum IgA levels showed prompt improvement in response to glucocorticoids in the IgG4-RD responder index.

CONCLUSIONS

Some patients diagnosed with IgG4-RD have high serum IgA levels. These patients may form a subgroup, characterized by good response to glucocorticoids, less frequent relapse, mildly elevated serum C-reactive protein levels, and possible complications of autoimmune diseases.

Recent advances in IgG4-related kidney disease

Recent advances in the management and understanding of immunoglobulin (Ig)G4-related kidney disease (RKD) have emphasized the importance of urgent treatment in IgG4-related tubulointerstitial nephritis. On the other hand, to avoid long-term glucocorticoid toxicity, strategies for early withdrawal of steroids or combination of immunosuppressants, such as rituximab, and the minimum dose of steroids have been pursued. However, disease recurrence after reducing or stopping steroid therapy hampers early withdrawal of glucocorticoid maintenance therapy. In addition, knowledge has accumulated in diagnostic approaches including differential diagnosis of anti-neutrophil cytoplasmic antibodies-associated vasculitis, idiopathic multicentric Castleman's disease, and Rosai-Dorfman disease with kidney lesion, which leads to earlier and precise diagnosis of IgG4-RKD. This review summarizes recent progress in the differential diagnosis of IgG4-RKD and related treatment strategies and recent topics of hypocomplementaemia, membranous glomerulonephritis, and IgG4-related pyelitis and periureteral lesion.

Idiopathic Multicentric Castleman Disease with Cutaneous Manifestation: Case Report

Castleman disease constitutes a rare class of lymphoproliferative disorders, with an estimated incidence of 21 to 25 per million patient years. The idiopathic subtype exhibits a significantly diverse clinical presentation, which can imitate many autoimmune, malignant, and infectious diseases. Cutaneous manifestations are uncommon and require in-depth investigation, especially when concurrent lymphadenopathy is present. A 79-year-old female, with a chronic, complicated erysipelas-like lesion, presented with bilaterally enlarged inguinal lymph nodes; after surgical excision, their histopathological examination revealed Castleman disease. Even though it is a benign condition, patients are often predisposed to developing certain types of malignancies, which can deteriorate their prognosis. An accurate and early diagnosis, along with effective treatment and prevention of recurrence, is of utmost importance in order to increase the patients’ overall survival and quality of life.

Immunoglobulin G4-related lymph node disease with an orbital mass mimicking Castleman disease: A case report

BACKGROUND

Immunoglobulin (Ig) G4-associated diseases are a group of systemic diseases involving multiple organs and are also known as IgG4-associated sclerosing diseases. IgG4-associated lymphadenopathy occurring in the lymph nodes is characterized by a lack of specificity due to its clinicopathological characteristics and must be differentiated from a variety of lesions, such as Castleman disease, lymphatic follicular reactive hyperplasia, and lymphoma.

CASE SUMMARY

A 65-year-old male patient, with Guillain-Barre syndrome for 5 years, presented to our hospital complaining of bilateral orbital mass for 2 years. After hospitalization, the results of the patient’s laboratory tests showed that immunoglobulin subgroup IgG4 was 33.90 g/L and IgG was 30.30 g/L, but serum interleukin-6 was normal. The pathological morphology of orbital mass and cervical lymph node were consistent, which showed that a large number of plasma cells and eosinophils were observed in the lymphatic follicles, and the interstitial fibrous tissue was proliferative. Immunohistochemistry showed that CD20 (B cells) (+), CD3 (T cells) (+), CD38 (+), IgG (+), IgG4 positive cells > 100/high powered field, and IgG4/IgG > 40%. Combined with clinical and immunohistochemical results, lymphadenopathy was consistent with Castleman disease-like IgG4-associated sclerosing disease. Prednisone acetate treatment was given at 40 mg/d. After 2 wk, the superficial lymph nodes and orbital masses shrank, and the IgG4 level decreased. As prednisone acetate was regularly used at a reduced dosage, no recurrence of the disease has been observed.

CONCLUSION

This case suggested that it is necessary to proceed cautiously in clinical practice with such patients, and immunoglobulin, complement, interleukin-6, C-reactive protein, and other examinations should be performed to confirm the diagnosis.

Cutaneous Manifestations of Castleman Disease: Histopathological Characteristics and Review of Literature

ABSTRACT

Castleman disease (CD) is a poorly understood lymphoproliferative disorder characterized by enlarged lymph nodes. The spectrum of differential diagnoses is wide, and it is hard to differentiate from other diseases. Cutaneous involvement of CD is rare, and studies that describe cutaneous dermatopathology of CD are scarce. The aim of this study was to collect case reports of CD with cutaneous manifestations and identify potential relevant histopathological features. We found that cases of CD with cutaneous manifestations often exhibited dermal lymphoid follicles with follicle center infiltration of lymphocytes and plasma cells. These dermal follicles also had regressive or atrophic germinal centers and were penetrated by hyalinized vessels. Patients with CD also consistently exhibited perivascular and deep dermal inflammatory infiltrate, primarily composed of lymphocytes and plasma cells. We intend to raise awareness of this rare entity and provide more histopathological information regarding its dermatological manifestations.

IgG4-related disease and idiopathic multicentric Castleman's disease: confusable immune-mediated disorders

IgG4-related disease (IgG4-RD) and idiopathic multicentric Castleman's disease (iMCD) are both rare systemic immune-mediated disorders. However, pathogenesis differs markedly between the two diseases, and differing therapeutic strategies are adopted: IgG4-RD is treated using a moderate dose of glucocorticoids or rituximab, while iMCD therapy involves an interleukin (IL)-6 targeted approach. Nonetheless, some clinical features of IgG4-RD and iMCD overlap, so differential diagnosis is sometimes difficult, even though the classification and diagnostic criteria of the diseases require careful exclusion of the other. The key findings in IgG4-RD are high IgG4/IgG ratio, allergic features, and germinal centre expansion involving T follicular helper cells, while iMCD involves polyclonal antibody production (high IgA and IgM levels), sheet-like mature plasma cell proliferation, and inflammatory features driven by IL-6. The distribution of organ involvement also provides important clues in both diseases. Particular attention should be given to differential diagnosis using combined clinical and/or pathological findings, because single features cannot distinguish IgG4-RD from iMCD. In the present review, we discuss the similarities and differences between IgG4-RD and iMCD, as well as how to distinguish the two diseases.

Afebrile Pneumonia in a Patient With Multicentric Castleman Disease on Siltuximab: Infection Without Fever on Anti-Interleukin-6 Therapy

Castleman disease is a lymphoproliferative disorder characterized by atypical lymph node hyperplasia and systemic symptoms; it can also affect the skin and blood counts. The condition is categorized by the extent of involvement (unicentric or multicentric) and the observed lymph node pathology (hyaline-vascular, plasma cell or mixed cellularity). Pathogenesis also has a role in the classification and treatment of multicentric Castleman disease; this variant can either be related to the presence of human herpesvirus-8 (HHV-8) infection or associated with POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal proteins and skin changes) syndrome, or idiopathic. The principal cytokine responsible for causing idiopathic multicentric Castleman disease (IMCD) is interleukin-6 (IL-6). Therefore, treatment with agents that bind to IL-6 (such as siltuximab) or block the IL-6 receptor (such as tocilizumab) has been used. We report a woman with IMCD who was successfully being treated with siltuximab; her cutaneous manifestations and systemic disease (lung and lymph nodes) improved within three months. However, nine months after starting siltuximab, she developed a worsening cough and new infiltrates in the right lung on positron emission tomography/computed tomography (PET/CT) scan; there were no other constitutional symptoms such as fever, night sweats or fatigue. Differential diagnosis included Castleman disease recurrence, lung neoplasm and infection. Her pulmonary symptoms and infiltrates on scan resolved after treatment with systemic levofloxacin, indicating that she had an antibiotic-sensitive afebrile pneumonia. We postulate that her siltuximab therapy blocked the IL-6-associated fever and constitutional symptoms that normally are a hallmark of pneumonia. Therefore, patients who are receiving medications such as siltuximab and tocilizumab that block the IL-6 pathway and impair the acute phase inflammatory response may fail to manifest constitutional symptoms such as fever when infected.

Clinical characteristics of a concurrent condition of IgG4-RD and Castleman's disease

IgG4-related disease (IgG4-RD) and Castleman's disease (CD) share similar clinical manifestations. When the histopathology coincides with the diagnosis of both IgG4-RD and CD, it is hard to depart the two disease entities utterly; here we call it IgG4-CD provisionally. In this study, we aim to review the clinical features of IgG4-CD. This study is based on a retrospective analysis of a prospectively acquired database. IgG4-CD was defined histopathologically in patients who fulfilled the diagnosis of both IgG4-RD and CD. Forty-five definite IgG4-RD and 16 multicentric CD (MCD) patients were recruited as controls. Clinical features including organ involvement, serum IgG4, IgG, IgE, ESR, CRP, and IL-6 levels were collected and analyzed. Fifteen patients (2.8%) out of 534 patients with IgG4-RD in China's largest prospective IgG4-RD and Mimicry cohort fulfilled the definition of IgG4-CD. There were 14 males and 1 female, whose mean age was 47 ± 18 years old, and the median disease duration before diagnosis was 12 (1-132) months. Eight patients have allergic disease history. IgG4-CD patients had more lymph node involvement (100 vs 57.8%, P < 0.01), while IgG4-RD patients had more submandibular (33.3 vs 77.1%, P < 0.01) and parotid gland (13.3 vs 40.9%, P < 0.05) affected. IgG4-CD patients had significantly higher levels of ESR, CRP, IgG, IgG1, IgG3, IgG4, and IgE than IgG4-RD patients. Compared with MCD patients, IgG4-CD patients showed higher incidence of salivary gland and paranasal sinus involvement, higher hemoglobin, eosinophil count, serum IgG4 level and IgG4/IgG ratio, and lower CRP, IL-6 levels, and IgG1/IgG, IgG2/IgG ratio. All patients with IgG4-CD exhibited relatively favorable outcomes. Both IgG4-RD and CD can involve multiple organs. There are a small group of patients who had clinical and pathological characteristics of both CD and IgG4-RD showed better clinical outcome. In the long-term prognosis of these patients, the relationship of CD and IgG4-RD is waiting to be further elucidated.

Polymyositis with elevated serum IgG4 levels and abundant IgG4+ plasma cell infiltration: A case report and literature review

INTRODUCTION

Polymyositis (PM) is a type of autoimmune, inflammatory myopathy. IgG4-related disease (IgG4-RD) is a recently recognized disease entity characterized by elevated serum IgG4 levels and IgG4 plasma-cell infiltration of various organs. However, several reports have described cases of other diseases that present with those features, suggesting the importance of careful differential diagnosis. Herein, we report the first case of PM with elevated serum IgG4 levels and IgG4 plasma cells in the muscles, mimicking IgG4-RD.A 73-year-old woman visited our hospital because of proximal muscle weakness of both thighs. Her blood test showed high levels of serum creatinine kinase, aldolase, and IgG4. Magnetic resonance imaging of the thighs showed muscle edema. Needle electromyography showed findings typical of myositis. Histological analysis of her left quadriceps revealed infiltration of IgG4 plasma cells as well as CD8 T cells. Scattered necrotic and regenerating muscle fibers with no specific findings for IgG4-RD (storiform fibrosis and obliterative phlebitis) were typical for PM. We diagnosed her condition as PM and treated her with 40 mg/day of prednisolone that decreased levels of muscle enzymes and improved muscle weakness.

CONCLUSION

Our case indicated that PM could present with high serum IgG4 levels and IgG4 plasma-cell infiltration, mimicking IgG4-RD. Although the mechanism of IgG4 elevation in such PM is unclear, our case highlights the necessity to recognize that high serum IgG4 levels and IgG4 plasma-cell infiltration in organs are not specific for IgG4-RD.

Distinct features distinguishing IgG4-related disease from multicentric Castleman's disease

Objectives

Differentiating IgG4-related disease (IgG4-RD) from multicentric Castleman’s disease (MCD) is challenging because both diseases present high serum IgG4. The objective of this study is to clarify the differences in characteristics and identify a clinically useful approach to differentiate these two diseases.

Methods

Forty-five consecutive patients with untreated active IgG4-RD and 33 patients with MCD were included in this study, who visited our institution from January 2000 to August 2016. The clinical and laboratory findings for the patients of the two diseases were compared. Various combinations of the distinctive findings were evaluated to identify the most efficient differentiating features between IgG4-RD and MCD.

Results

The levels of serum IgG4 were not different between the two diseases. Orbits, lacrimal glands, salivary glands or pancreas were involved in 88.9% of IgG4-RD cases and only in 3.0% of MCD cases. All MCD cases involved lymph nodes. Atopic history was characteristic for IgG4-RD. The levels of C reactive protein (CRP) with a cut-off of 0.80 mg/dL and IgA with a cut-off of 330 mg/dL were the most distinctive. The combination of ‘Orbits, lacrimal glands, salivary glands or pancreas involvement, atopic history, or non-involvement of lymph node’ and ‘CRP ≤ 0.8 mg/dL or IgA ≤ 330 mg/dL’ yielded the probability of 97.8% in IgG4-RD, while that of 3.0 % in patients with MCD.

Conclusions

Our study revealed distinct features between IgG4-RD and MCD. Differentiating between the diseases based on those distinct features, including distribution of organ involvement, atopic history, levels of IgA and CRP, was a useful approach.

IgG4-related skin disease may have distinct systemic manifestations: a systematic review

IgG4-related disease (IgG4-RD) is an increasingly prevalent protean multisystem disorder characterized by single or multi-organ infiltration of IgG4-bearing plasma cells. Skin involvement has been recognized and is relevant to proper diagnosis. A systematic literature review of 50 cases involving the skin reveals that patients with IgG4-related skin disease show predominant involvement of the head and neck and have a distinct pattern of systemic involvement, also favoring the head and neck - lymphatics, orbit, salivary, and lacrimal glands - but generally lacking pancreaticobiliary involvement (16% of cases), which by contrast is a predominant manifestation in systemic IgG4-RD (60% with pancreaticobiliary involvement). We summarize clinical and pathologic descriptive data from this systematic review. We review differential diagnosis and propose a diagnostic scheme for stratifying probability of disease based upon comprehensive integration of clinical, histopathologic, and laboratory data. Plasmacyte infiltration and storiform fibrosis are prominent in IgG4-related skin disease, but obliterative venulitis is less common than in the prototypical IgG4-related disease manifestation of autoimmune pancreatitis. IgG4 tissue and serum values, with a mean (±95% CI) in the reviewed cases of 132.8 ± 32.6 IgG4-positive plasma cells per high-power field and 580 ± 183.8 mg/dl, respectively, are incorporated into the suggested criteria. The distinct set of manifestations identified by this systematic review and the proposed diagnostic considerations, while requiring further validation in prospective studies, highlight the need to consider that IgG4-related skin disease defines a unique systemic disease complex along the spectrum of IgG4-RD.

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome with remarkably elevated serum IgG4

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a rare inflammatory disorder with unknown etiology, while the evidence of the association between IgG4 and inflammatory disorders is accumulating. We present the first report of a patient with SAPHO syndrome with remarkably elevated serum IgG4. The clinical features of this 45-year-old male patient included pain of the anterior chest wall and right elbow, bone marrow edema in the ulna suggested by magnetic resonance imaging (MRI), the “bull’s head” sign on the bone scintigraphy, and remarkably increased IgG4 and interleukin-6. This report may indicate a spectrum of diseases with serum IgG4 elevation broader than previously reported. Moreover, it also provides information on the underlying abnormal immune response in SAPHO syndrome.

Overlap of IgG4-related Disease and Multicentric Castleman's Disease in a Patient with Skin Lesions

A 59-year-old man presented with multiple dark red erythemas with induration, anemia, and polyclonal hypergammaglobulinemia. A skin biopsy revealed the infiltration of lymphocytes and plasma cells and he was initially diagnosed with multicentric Castleman's disease (MCD). Glucocorticoid treatment was only partially effective. Four years later, the patient's bilateral lacrimal glands gradually became enlarged and a biopsy revealed dense lymphocyte and plasma cell infiltration with an IgG4+/IgG+ plasma cell ratio of 70%. The patient was diagnosed with IgG4-related disease (RD). Rituximab only had a slight effect. This case demonstrates that overlapping features of IgG4-RD and MCD may present in a single patient, which suggests a shared pathogenesis.

Multicentric Castleman Disease With Tubulointerstitial Nephritis Mimicking IgG4-related Disease: Two Case Reports

Multicentric Castleman disease is a benign lymphoproliferative disorder with heterogenous clinical symptoms and involves systemic organs in addition to lymph nodes. Elevated serum IgG4 levels and IgG4-positive plasma cell (IgG4+PC) infiltrates have been reported in lymph nodes, lung and skin in some multicentric Castleman disease cases, resembling IgG4-related disease (IgG4-RD) histologically. However, no report has been available regarding IgG4+PC infiltration in the kidneys of multicentric Castleman disease. Here, we report 2 cases of multicentric Castleman disease complicated by IgG4-related disease (IgG4-RD) histologically. However, there has been no report published on PC-rich tubulointerstitial nephritis, lymphadenopathy, with numerous IgG4+PC infiltration, and elevated serum IgG4 levels, mimicking IgG4-RD. The blood examinations revealed systemic inflammation and elevated C-reactive protein and interleukin-6 levels. Corticosteroid therapy was partially effective in both cases, and combination therapy of corticosteroid and tocilizumab was needed in both cases. Moreover, after triple therapy with corticosteroid, rituximab and cyclophosphamide were used in 1 case to tame the severe inflammation. The present cases suggest that if continuously elevated serum C-reactive protein levels and partial corticosteroid responsiveness are encountered, multicentric Castleman disease should be considered rather than IgG4-RD as a differential diagnosis even if serum IgG4 is elevated and IgG4+PCs infiltrate systemic organs.

Enhanced IgG4 production by follicular helper 2 T cells and the involvement of follicular helper 1 T cells in the pathogenesis of IgG4-related disease

Background

The aim of this study was to elucidate the function of circulating follicular helper T (Tfh) cell subsets in helping B cells in patients with active, untreated IgG4-related disease (IgG4-RD) and determine their relationship with disease activity.

Methods

Seventeen consecutive patients with active, untreated IgG4-RD, 20 with primary Sjögren syndrome (pSS), 5 with multicentric Castleman’s disease (MCD), and 12 healthy controls (HC) were enrolled. Tfh cell subset function was evaluated by co-culture with naïve B cells in vitro. Activated Tfh cell subsets were defined as a CCR7^lowPD-1^high subset among Tfh cell subsets. Disease activity was evaluated by IgG4-RD responder index (IgG4-RD RI) score.

Results

The number of Tfh2 cells was significantly higher in IgG4-RD compared to pSS, MCD, or HC, and correlated with serum IgG4 level or the number of plasmablasts. In vitro, Tfh2 cells more efficiently induced the differentiation of naïve B cells into plasmablasts compared to Tfh1 or Tfh17 cells. Of note, while IgG production in culture supernatants of Tfh2 cells was comparable between IgG4-RD and HC, IgG4 production was significantly higher with Tfh2 cells from patients with IgG4-RD than in those from HC. Accordingly, the IgG4:IgG ratio in culture supernatants was also significantly higher with Tfh2 cells from IgG4-RD compared to HC. Moreover, the number of activated Tfh2 cells was higher in IgG4-RD compared to pSS, MCD, or HC, and strongly correlated with IgG4-RD RI score in the baseline active phase. Particularly, the number of activated Tfh2 cells was associated with the number of affected organs and serum IgG4 level. Importantly, the number of activated Tfh2 cells was decreased after glucocorticoid treatment and paralleled disease improvement. Moreover, the number of activated Tfh1 cells was also increased in IgG4-RD compared to pSS, MCD, or HC, correlating with IgG4-RD RI score, but not with serum IgG4 level.

Conclusions

Tfh2 cells, but not Tfh1 or Tfh17 cells, induce the differentiation of naïve B cells into plasmablasts and enhanced production of IgG4 in patients with active, untreated IgG4-RD. Furthermore, activated Tfh2 cells reflect disease activity, suggesting the involvement of this T cell subset in the pathogenesis of IgG4-RD. Interestingly, the number of activated Tfh1 cells was also increased in IgG4-RD, correlating with disease activity but not with serum IgG4 level, suggesting the involvement of Tfh1 cells but not in the process of IgG4 production in patients with IgG4-RD.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1064-4) contains supplementary material, which is available to authorized users.

Dermatologic disorders in 118 patients with autoimmune (immunoglobulin G4-related) pancreatitis: a retrospective cohort analysis

BACKGROUND

Autoimmune pancreatitis is the prototypical manifestation of immunoglobulin G4-related disease, a fibroinflammatory syndrome that can affect virtually any organ. Rarely, skin involvement has been reported in immunoglobulin G4-related disease. Isolated case reports have described other distinct associated dermatoses.

OBJECTIVE

Our objective was to determine the frequency and nature of dermatologic manifestations of immunoglobulin G4-related disease in patients with autoimmune pancreatitis.

METHODS

Retrospective analysis of dermatologic conditions of patients with autoimmune pancreatitis.

RESULTS

Among the 118 identified patients, 31 (26.3%) had a dermatologic diagnosis [mean (standard deviation; SD) follow-up 5.9 (4.6) years]. Two patients (1.7%) had necrobiotic xanthogranuloma; three (2.5%) had another xanthomatous or xanthogranulomatous process. One patient (0.8%) had pemphigus erythematosus. No patient had immunoglobulin G4-related skin disease.

CONCLUSION

Skin involvement in immunoglobulin G4-related disease appears to be rare. A disproportionately high number of patients had xanthomatous or xanthogranulomatous processes, including necrobiotic xanthogranuloma. It remains unclear whether the association between immunoglobulin G4-related disease and necrobiotic xanthogranuloma or other xantho(granulo)matous processes represents shared pathophysiology, a mutual underlying driver, or coincidence, though the results of this study cast doubt on the latter. Although pemphigus was not reported in immunoglobulin G4-related disease previously, the prominent role of the immunoglobulin G4 subclass in each condition makes this association intriguing.

IgG4-related lung disease with atypical CT imaging: a case report

IgG4-related lung disease is a rare disease, diagnosed when typical pathologic features are seen in the context of increased serum levels of IgG4 and the elevated tissue's IgG4-positive plasma cells. Here we reported the case of a 24-year-old woman with IgG4-related lung disease. This patient presented with fever, cough and shortness of breath. Thoracic computed tomography (CT) images demonstrated multiple nodules or masses with high density in both lungs, and thickened interlobular septa. The 'halo sign' was observed around the high-density lesions of the upper lobes. This range of CT images' characteristics is atypical, which differs from previous reports of this condition.

Clinicopathologic analysis of IgG4-related skin disease

IgG4-related disease is a recently recognized systemic syndrome characterized by mass-forming lesions with lymphoplasmacytic infiltration, increase in the number of IgG4(+) cells in affected tissues and elevation of serum IgG4 levels. In 2009, we were the first to report skin lesions in patients with IgG4-related disease, but no large case series has been reported and clinicopathological findings remain unclear. To clarify these features, we herein report 10 patients (9 men and 1 woman; median age, 64 years; age range, 46-81 years) with IgG4-related skin disease. All patients had erythematous and itchy plaques or subcutaneous nodules on the skin of the head and neck, particularly in the periauricular, cheek, and mandible regions, except for one patient, whose forearm and waist skin were affected. In addition, eight patients had extracutaneous lesions: these were found on the lymph nodes in six patients, the lacrimal glands in three patients, the parotid glands in three patients, and the kidney in one patient. Histologically examined extracutaneous lesions were consistent with IgG4-related disease; five of six lymph node lesions showed progressively transformed germinal centers-type IgG4-related lymphadenopathy. Cases of IgG4-related skin disease were classified into two histological patterns: those exhibiting a nodular dermatitis pattern and those with a subcutaneous nodule pattern. The infiltrate was rich in plasma cells, small lymphocytes, and eosinophils; the majority of the plasma cells were IgG4(+). The IgG4(+) cell count was 49-396 per high-power field (mean±s.d., 172±129), with an IgG4(+)/IgG(+) cell ratio ranging from 62 to 92%. Serum IgG4 levels were elevated in all examined patients. In conclusion, patients with IgG4-related skin disease had uniform clinicopathology. Lesions were frequently present on the skin of the periauricular, cheek, and mandible regions, and were frequently accompanied by IgG4-related lymphadenopathy.

IgG4-related ocular adnexal disease mimicking thyroid-associated orbitopathy

A 72-year-old man presented with bilateral eyelid swelling and redness. An orbital CT scan showed bilateral proptosis, extraocular muscle enlargement and swollen lacrimal glands, mimicking thyroid-associated orbitopathy (TAO) with Hashimoto's thyroiditis (HT). During the patient's clinical course, spontaneous remission of lung consolidation (35 × 26 mm) was seen. A diagnosis of IgG4-related disease (IgG4-RD) was made based on an elevated serum IgG4 level (1,020 mg/dL; normal, 4-108), predominance of IgG4-positive plasma cells (IgG4/IgG: 35/70 in HPF) in the lacrimal glands and typical features of Mikulicz's disease. This report provides a novel description of this unusual disease entity among HT, TAO and IgG4-RD.