IgG4-related diseases (IgG-RDs) are a group of fibroinflammatory diseases that affect a variety of tissues, resulting in tumour-like effects and/or organ dysfunction. Monoclonal gammopathies (MGPs) are a group of disorders characterized by clonal proliferation of plasma cells or lymphoid cells resulting in the secretion of a monoclonal immunoglobulin. Cases of MGPs in IgG4-RDs coexisting with plasma cell dyscrasias and lymphoid neoplasms have been reported over the past few years. Therefore, the results of examinations of M protein in IgG4-RD patients should be interpreted with caution. Herein, we report the case of a 58-year-old male with a history of type 2 diabetes who presented with submandibular masses, anosmia, swollen lymph nodes, proteinuria, and renal impairment. Laboratory tests revealed hyperglobulinemia and elevated levels of IgG4 (124 g/L) and serum-free light chains (sFLCs). Serum protein electrophoresis (SPEP) revealed an M spike of 5.6 g/dL, and immunofixation electrophoresis (IPE) revealed biclonal IgG-κ and IgG-λ. The patient underwent bone marrow, lymph node, and kidney biopsy, which ruled out plasma cell disorders and lymphoma. He was finally diagnosed with an IgG4-RD comorbid with diabetic nephropathy. The findings in this case highlight that significant activation of B cells in IgG4-RD patients, especially those with multiorgan involvement can lead to significant hyperglobulinemia and high sFLC and IgG4 levels, which are more pronounced in the setting of renal impairment. Relatively high concentrations of polyclonal IgG4 can give rise to a focal band bridging the β and γ fractions, which may mimic the appearance of a monoclonal band on SPEP and monoclonal gammaglobulinemia in IFE. The patient experienced considerable improvement in his symptoms after rituximab combined with glucocorticoid therapy, and a monoclonal immunoglobulin was not detected.

IgG4-related disease is an immune-mediated fibroinflammatory condition. Isolated manifestation in the spine as hypertrophic pachymeningitis is very rare and the mass-like lesion on MRI often mimic tumour or infection. Patients would present with symptoms that result from mass effect or neurovascular compression. Studies showed that serum and CSF IgG4 levels are rarely informative, and therefore, tissue biopsy is crucial for accurate diagnosis. Apart from supporting the diagnosis, MRI is helpful in delineating the extent of disease and follow-up after treatment. A 18F-FDG PET/CT scan is useful in detecting systemic manifestations of IgG4-related disease. Although IgG4-related disease generally responds well to corticosteroid at inflammatory state, relapse is not uncommon. Current treatment strategies for IgG4-related hypertrophic pachymeningitis are high dose corticosteroid therapy and early decompressive surgery to avoid chronic neurological complications. We described a case of a 27-year-old gentleman complaining of lower limb weakness and numbness. MRI showed a mass-like epidural lesion at the thoracic spine causing cord compression. Open biopsy of the epidural mass demonstrated histopathological characteristics of IgG4-related disease. Patient responded well to early surgical decompression of the spinal cord and corticosteroid as evidenced by symptom improvement and resolving mass on subsequent MRI study. However, a follow-up MRI revealed disease recurrence years later.

UNASSIGNED: Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is frequently accompanied with type 1 autoimmune pancreatitis (AIP). Isolated IgG4-SC which is not accompanied with AIP is uncommon in clinical practice, and its manifestations are similar to those of hilar cholangiocarcinoma.
UNASSIGNED: A 55-year-old male presented with persistent aggravation of icteric sclera and skin. He was initially diagnosed with hilar cholangiocarcinoma and underwent surgery. However, positive IgG4 plasma cells were found in the surgical specimens. Thus, a pathological diagnosis of IgG4-SC was established. After that, steroid therapy was given and initially effective. But he was steroid dependent, and then received rituximab therapy twice. Unfortunately, the response to rituximab therapy was poor.
UNASSIGNED: It is crucial to differentiate isolated IgG4-SC from hilar cholangiocarcinoma to avoid unnecessary surgery. Future studies should further explore effective treatment strategy in patients who do not respond to steroids therapy. It is also required to develop novel and accurate diagnostic approaches to avoid unnecessary surgical procedures.

UNASSIGNED: Intracranial inflammatory pseudotumours (IPT) are rare entities that frequently lead to misdiagnosis with malignant lesions. The identification of these lesions is difficult, but important to avoid inadvertent iatrogenicity and to adjust therapeutic protocols.
UNASSIGNED: We report the case of a 30-year-old man who presented a single tonic-clonic seizure. Brain imaging showed a right frontal lesion with intra and extra axial components. Facing the radiologic presentation, a brain tumor was suspected, thus the patient underwent surgery. Pathological exam concluded to a plasma cell granuloma. A whole-body CT-scan showed only a thoracic aortitis. Complete blood work studies came back negative. The patient was also tested for an array of antibodies among which antinuclear antibodies were positive (blood level superior to 1/100). CSF evaluation revealed clear fluid with normal glucose concentration, normal protein levels and lymphocytic pleocytosis. Finally, IgG-4 plasma levels were elevated which led to the diagnosis of an IgG4-RD. The patient was put under prednisolone with a favorable outcome.
UNASSIGNED: IPT have several etiologies, among which IgG4 related disease may be one of the less known as only 2 cases have previously been reported. Herein, we report a new case of a young man who presented for seizures related to an intracranial lesion of an IgG4 related disease. The challenge is to suspect such conditions to avoid unnecessary surgeries.

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Coronavirus disease 19 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is affecting the world with a surge in cases. A variety of autoimmune diseases occur after SARS-CoV-2 infection or vaccination, of which IgG4-related disease (IgG4-RD) is an important type. IgG4-RD can involve multiple organs of the body. The ocular manifestation of IgG4-RD is called IgG4-related ophthalmic disease (IgG4-ROD). We herein report a patient diagnosed with IgG4-ROD. The patient developed ptosis and vision loss after SARS-CoV-2 vaccination, and the symptoms worsened after SARS-CoV-2 infection. After excluding other diseases like myasthenia gravis and Eaton-Lambert syndrome that may cause ptosis, the diagnosis of IgG4-ROD was confirmed by pathological examination. We discussed the predisposing factors, diagnosis and treatment of this patient to provide a more empirical and theoretical basis for clinical diagnosis and treatment. We conducted a literature review of previously reported cases of IgG4-RD following SARS-CoV-2 infection or vaccination. We retrieved a total of 9 cases, of which 5 developed symptoms after vaccination and 4 after infection. Demographic and clinical characteristics were summarized. In conclusion, our case represents the first case of proven IgG4-ROD after COVID-19 vaccination. We believe that IgG4-ROD and SARS-CoV-2 infection or vaccination are closely related, and the immune system disorder caused by SARS-CoV-2 infection or vaccination may be a key factor in the pathogenesis of IgG4-RD. But for now, there is no direct evidence that there is a causal relationship between SARS-CoV-2 infection or vaccination and IgG4-ROD, which still needs more research and exploration to confirm.

We report a case of IgG4-related disease (IgG4-RD) with marked eosinophilia. A 79-year-old woman was admitted due to diarrhoea and weight loss. Cervical lymphadenopathy, bilateral submandibular glands swelling, anaemia (Hb8.5 g/dl), hypereosinophilia (9750/μl), elevated serum creatinine (1.57 mg/dl), pancreatic amylase (191 IU/l), and IgG4 (3380 mg/dl) were found. Diffusion-weighted image on magnetic resonance imaging showed high-intensity signals inside both the pancreas and the kidneys. The echogram of submandibular glands revealed cobblestone pattern. Kidney biopsy revealed acute tubulointerstitial nephritis. Biopsies of lip, gastrointestinal tract, and bone marrow showed infiltration of lymphoplasmacytic cells and IgG4-positive plasma cells (30-67/HPF). Gastrointestinal and bone marrow biopsies also showed eosinophilic infiltration. Adrenal insufficiency, rheumatic disease, tuberculosis, parasite infection, drug-induced eosinophilia, and eosinophilic leukaemia were all ruled out. We started treatment with 40 mg of prednisolone (PSL) and her general condition rapidly improved. The eosinophil count, serum IgG4, and serum creatinine decreased. We gradually tapered PSL and maintained 5 mg/day. During the 5 years of treatment, she had no recurrence of the symptom. According to the 2019 American College of Rheumatology/European League Against Rheumatism classification criteria for IgG4-RD, eosinophils >3000/μl is one of the exclusion criteria. If we comply with this criterion, the diagnosis of IgG4-RD should be avoided. However, our case fit the diagnostic criteria of type I autoimmune pancreatitis, IgG4-related sialadenitis, and global diagnosis of IgG4-RD. We finally diagnosed our case as IgG4-RD with secondary hypereosinophilic syndrome. This case suggests that IgG4-RD with eosinophils >3000/μl does exist in the real world.

We report a case of immunoglobulin (ig)-g4-related thyroiditis associated with graves\' disease. a 45-year-old man was diagnosed with graves\' disease due to asymptomatic enlarged thyroid gland and high serum levels of thyrotropin receptor antibodies and thyroid hormones. surgical resection of the thyroid gland was performed because of further thyroid gland enlargement and severe fluctuations in the thyroid hormonal levels, despite medical therapy with a combination of an antithyroid drug and a thyroid hormone preparation. macroscopic examination of the resected thyroid gland revealed a grayish-white diffuse swelling, and histopathological findings revealed follicular destruction, chronic inflammatory cell infiltration with diffuse igg4-positive plasma cells (IgG4/IgG >40%), storiform fibrosis, and phlebitis obliterans throughout the thyroid tissue. Additionally, there were small foci of high columnar follicular components with scalloping, resembling Graves\' disease. We propose that all patients with Graves\' disease should be evaluated for coexisting IgG4-related thyroiditis to detect ophthalmopathies as soon as possible.

IgG4 masses in the bilateral distal ureters are rare and frequently misdiagnosed. The present study reported the case of a 55-year-old male patient with IgG4-related disease (IgG4-RD) who had symmetrical soft tissue masses of the bilateral distal ureters found on magnetic resonance imaging (MRI) with a significant increase in the serum levels of IL-6, IgG4 and IgE. Regarding treatment, this patient received prednisone acetate tablets (40 mg/day) and mycophenolate mofetil dispersible tablets (1 g/day). During the follow-up, significant reductions in the levels of IgG4 and IgE were found after 30 days. MRI after 6 months indicated complete disappearance of the masses. The prognosis has been good so far. In clinical practice, it is necessary to consider the possibility of IgG4-RD in cases with soft tissue masses surrounding both ureters and elevated levels of serum IgG4.

We present a case of a patient with recurrent prostate cancer after treatment for favorable intermediate risk cancer. There was an exceptionally steep increase in PSA from <0.5 to 130ng/mL in 27 months accompanied with the development of bone metastasis. The PSA increase was unexpected. We suspect that this unusual development of metastases must have been caused by an impairment of the immune system caused by his IgG4 disease, and this may have allowed residual prostate cancer cells in the prostate to spread quickly. The influence of IgG4 on cancer is debated.