BACKGROUND: IgG4-related diseases are very uncommon, and its diagnosis and treatment are complicated as it encompasses multiple disciplines.
METHODS: A 77-year-old woman was admitted with a jaw mass and nausea and vomiting. Laboratory tests showed elevated serum IgG4, pituitary MRI suggested thickening of the pituitary stalk, and head and neck CT suggested orbital and mandibular masses. Patients with mandibular mass were diagnosed with Mikulicz\'s disease with IgG4-related hypophysitis. We found no other evidence of causing thickening of the pituitary stalk. She was given oral prednisolone 30 mg daily, and her nausea and vomiting improved significantly, and the mandibular and ocular masses decreased in size.
CONCLUSIONS: Mikulicz\'s disease combined with IgG4-related hypophysitis is a rare case of IgG4-RD in elderly women. IgG4-RD is one of the causes of head and neck exocrine gland mass and pituitary stalk thickening in the elderly.

BACKGROUND: Sjögren\'s Syndrome (SS) is an inflammatory autoimmune disease, and Mikulicz\'s disease (MD) is a lymphoproliferative disorder. Both MD and SS are more common in middle-aged female, and the dry eyes could be presented in both of them with different degree. The MD patients are characterized by symmetrical swelling of the lacrimal glands which also can occur in the early stage of SS. And the imaging findings between early stage of SS and MD are lack of specificity. Therefore, SS and MD have similarities in the clinical manifestations, imaging and pathological findings and are confused in diagnosis.
METHODS: A 51-year-old female patient presented with bilateral swelling of the upper eyelids for 2 years. She also reported having dry mouth and dry eyes which could be tolerated. The Schirmer\'s test result is positive and the laboratory tests indicate serum total IgG increased. In the bilateral lacrimal gland area could palpate soft masses. The orbital magnetic resonance imaging (MRI) examination showed bilateral lacrimal gland prolapse. While the histopathological result was considered as MD. The immunohistochemical (IHC) staining results were positive for IgG and negative for IgG4. To clarify the diagnosis, SS-related laboratory tests were performed: anti-SSA antibody (+++), anti-SSB antibody (+++), anti-Ro-52 antibody (+++). With a comprehensive consideration, the final diagnosis was SS.
CONCLUSIONS: When the clinical manifestations are atypical, it is necessary to pay attention to the differential diagnosis of SS and MD.

Immunoglobulin G4-related disease (IgG4 RD) has a fair prognosis but its diagnosis has been difficult due to the condition\'s wide range of clinical manifestations, limited awareness among common practitioners, and various differentials. Here, we present a case of an elderly male who presented with recurrent dental caries, recurrent sinusitis, persistent dry mouth, and dry eyes along with bilateral parotid gland enlargement without any lymphadenopathy. The patient was evaluated further and found to have elevated levels of IgG4 and on histopathological examination of the parotid gland showed lymphocytic infiltrate with germinal centers without any granulomatous lesions and IgG4-positive plasma cells on immunohistochemistry (IHC). The patient was diagnosed with IgG4 RD and was started on corticosteroids, after which there was a symptomatic improvement.

Immunoglobulin G4-related disease (IgG4-RD) is a recently established systemic disease that is characteristically associated with elevated serum immunoglobulin G4 (IgG4) levels and believed to be caused by autoimmune mechanisms. The clinical features of IgG4-RD include (i) systemic distribution, (ii) imaging findings of swelling, nodules, and/or wall thickening, (iii) high serum IgG4 levels, (iv) abundant IgG4-bearing plasma cell infiltration and fibrosis in affected organs, (v) a favorable response to corticosteroid therapy, and (vi) coexistence with other IgG4-RD manifestations simultaneously or in a metachronous fashion. The concept of IgG4-RD was established based on the culmination of specific discoveries. Specifically, a close association between autoimmune pancreatitis (AIP) and high serum IgG4 levels, massive IgG4-bearing plasma cell infiltration in pancreatic tissues affected by AIP, and systemic other organ involvements in AIP with similar IgG4-bearing plasma cell features opened the gateway from AIP to IgG4-RD. The systemic distribution of IgG4-RD seems to be capable of affecting every organ, causing well-established members including AIP, lacrimal and salivary gland lesions such as Mikulicz\'s disease, respiratory diseases, sclerosing cholangitis, kidney diseases, and retroperitoneal fibrosis. IgG4-RD has been diagnosed worldwide, and international collaboration efforts on the disease have led to consensus publications on its nomenclature, pathology findings, and management approach. The algorithms developed for the comprehensive diagnostic criteria for IgG4-RD have remarkably increased detection sensitivity. Oral glucocorticoids are the first-line agents for remission induction, and certain patients with high disease activity may benefit from maintenance therapy afterwards. Originally, IgG4-RD had been considered reversible and to have a good prognosis; however, long-term afflictions sometimes result in transition to advanced-stage conditions with dysfunction and/or complicating malignancy. The immunological abnormalities in IgG4-RD have been reported in both innate and adaptive immune systems; however, it remains unclear whether IgG4 has a pathogenic role or a protective one in disease onset and progression.

Mikulicz\'s disease is a unique condition involving the enlargement of the lacrimal and salivary glands, similar to that observed in Sjogren\'s syndrome; however, Mikulicz\'s disease is clinically characterized by infrequent autoimmune reactions and responsiveness to glucocorticoid treatment. The ultrasound features of the lacrimal and salivary glands in patients with IgG4-Mikulicz\'s disease were characterized by multiple hypoechoic areas of varying sizes within the enlarged glands. IgG4 serum level was also elevated, in contrast to the detection of normal levels in Sjogren\'s syndrome. In this article, we intended to illustrate a case of Mikulicz\'s disease with clinical and imaging features.

IgG4-related disease (IgG4-RD) is a fascinating clinical entity first reported in this century in Japan, and includes a wide variety of diseases, such as formerly named Mikulicz\'s disease (MD), autoimmune pancreatitis (AIP), interstitial nephritis, prostatitis and retroperitoneal fibrosis. The Japanese IgG4 team organized by the Ministry of Health, Labor and Welfare (MHLW) of Japan has published the first criteria, comprehensive diagnostic (CD) criteria for IgG-RD 2011. Thereafter, IgG4-RD has been accepted widely and many cases have been reported from all over the world. Several problems have arisen in clinical practice, however, including the difficulty obtaining biopsy samples, and the sensitivity and specificity in cut off level of serum IgG4 and impaired immunostaining of IgG4. Given these situations, the Japanese IgG4 team has updated the 2011 comprehensive diagnostic criteria for IgG4-RD and propose the 2020 revised comprehensive diagnostic (RCD) criteria for IgG4-RD, which consists of 3 domains; 1) Clinical and radiological features, 2) Serological diagnosis and 3) Pathological diagnosis. In addition, the new pathological diagnosis is composed by three sub-items including storiform fibrosis and obliterative phlebitis.

According to a new concept for the classification and division of autoimmune diseases, Mikulicz\'s disease and Küttner\'s tumor belong to immunoglobulin G4-related diseases (IgG4-RD) and fulfil their diagnostic criteria. The aim of this study was to summarize the new classification concepts of IgG4-RD in the head and neck area and to review their clinical, histopathological and serologic criteria and the methods used in the diagnostic workup with respect to their advantages, limitations and differentiative value. The PubMed, Web of Science, Google Scholar, and Scopus databases were searched for articles published between 2009 and 2019 using the following key words: IgG4-related diseases, Mikulicz\'s disease, Küttner\'s tumor, salivary glands, xerostomia. Results of the review of the literature revealed that Mikulicz\'s disease and Küttner\'s tumor fulfil the same diagnostic criteria but may manifest different clinical symptoms which determine the choice of the different diagnostic tools.

Immunoglobulin G4-related disease (IgG4-RD) is a new disease entity of rare and complex immune-mediated fibroinflammatory conditions that can affect any organ. The concomitance of IgG4 sclerosing sialadenitis and dacryoadenitis with rhinosinusitis is extremely rare. We report a case of IgG4 sclerosing sialadenitis and dacryoadenitis (Mikulicz\'s disease) diagnosed in a middle-aged African American man with a long-standing history of chronic rhinosinusitis who presented with progressively worsening bilateral salivary and lacrimal glands swelling. Imaging revealed pansinusitis, symmetric enlargement of the lacrimal glands, parotid glands, and submandibular glands. Serological IgG4 level was significantly elevated and the diagnosis of IgG4 sclerosing sialadenitis was confirmed by histopathology. A robust clinical response in the facial swelling and nasal manifestations was noted after the initiation of immunotherapy with corticosteroids.

Mikulicz\'s disease (MD), an immunoglobulin G4 (IgG4)-related disease, is a fibrosis-associated inflammatory disease characterized by painless bilat- eral swelling of lacrimal and salivary glands. Although thrombocytopenia is associated with many rheumatologic disorders, it is rare in IgG4-related MD. This novel study aims to report a rare case of IgG4-related MD complicated with severe autoimmune thrombocytopenia without any hemato- logical malignancies and review all cases of IgG4-related disease associated with thrombocytopenia in the literature.

Mikulicz\'s disease is one of the IgG4-related diseases (IgG4-RDs) that involves the cardiovascular system; however, small-sized vasculitis is rare in IgG4-related diseases. A 64-year-old man presented with distal occlusive disease and developed left cerebrovascular infarction with occlusion of the middle cerebral artery and diseased temporal artery branches. He underwent superficial temporal artery-middle cerebral artery anastomosis surgery. Histology of the temporal artery biopsy showed smooth muscle cell proliferation with many IgG4-positive plasma cells. He then developed salivary gland inflammation, and Mikulicz\'s disease was diagnosed. Small-sized occlusive vasculitis was observed in this IgG4-RD. Low-dose corticosteroid therapy is effective in preventing progressive occlusive disease.