Kikuchi-Fujimoto disease (KFD) is a benign, self-limiting histiocytic necrotizing lymphadenitis systemic disorder with unknown etiology. KFD has been known for half a century, but difficulties in distinguishing it remain. Its diagnostic significance is related to the increasing prevalence of KFD with autoimmune diseases in various timeframes. Systemic lupus erythematosus (SLE) is the most prevalent autoimmune connective tissue disease (AICTD) appearing alongside KFD. An 18-year-old female presented with acute muscle weakness, shortness of breath, fever, and significant weight loss for 5 months before admission. Pain and morning joint stiffness had been felt for 9 months. One year ago, she lumped her right neck and was diagnosed with KFD from the excision biopsy and immunohistochemical staining (CD68). Creatine-kinase enzymes and C-Reactive protein were elevated with a high anti-Ku and anti-Jo-1 negative level. There was a low level of complements, high anti-nuclear antibody titer, with positive anti-SS-A. Sialometry and Schirmer test showed reduced salivary and lacrimal gland production. We diagnosed this patient as having an overlap syndrome preceded by KFD. The AICTD involved was Sjögren\'s syndrome and SLE. Although KFD is considered a self-limiting disease, its occurrence should be noticed regarding the possibility of other autoimmune conditions. KFD usually coincides with AICTD, although it could also precede or occur afterward. This case is reported to raise awareness of the overlap syndrome preceded by KFD.

Primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and autoimmune hepatitis (AIH) are distinct liver diseases. Cases combining PBC and PSC, are extremely rare. Here, we present a case of a 39-year-old woman with a history of colonic Crohn\'s disease treated with azathioprine. Discontinuation of the medication was prompted by abnormal liver function tests, but subsequent evaluations revealed persistent liver injury. Extensive diagnostic investigations, including imaging, serological tests, and liver biopsy, were conducted leading to a diagnosis of PBC-PSC overlap syndrome based on the presence of concentric lamellar fibrosis and chronic non-suppurative destructive cholangitis. The patient responded well to ursodeoxycholic acid treatment. This case emphasizes the importance of recognizing and diagnosing rare overlap syndromes, particularly those involving PBC and PSC, to ensure appropriate management and improve patient outcomes.

Primary sclerosing cholangitis (PSC), autoimmune hepatitis (AIH), and ulcerative colitis (UC) are immune diseases of the digestive system. Some patients develop overlap syndrome, the presentation of two or more of the clinical, biochemical, immunological, and histological features of these conditions simultaneously or sequentially. The incidence of UC in PSC-AIH overlap syndrome is as high as 50%. In contrast, PSC-AIH overlap syndrome is rare in UC patients. However, because it has a low prevalence and has been studied in less detail, PSC is often misdiagnosed as primary biliary cholangitis (PBC) in its early stage. Herein, we reported a case of a 38-year-old male patient who presented to a clinician in 2014 with irregular bowel habits. A colonoscopy suggested UC. In 2016, the patient was found to have abnormal liver function and was diagnosed with PBC by pathology. He was treated with ursodeoxycholic acid (UDCA) but this had no effect on his liver function. Additional liver biopsies in 2018 indicated PBC-AIH overlap syndrome. The patient refused hormone therapy for personal reasons. Following UDCA monotherapy, his liver function remained abnormal. The patient was reexamined after repeated abnormal liver function tests and bowel symptoms. Systematic laboratory testing, imaging diagnosis, colonoscopy, liver biopsy, and various pathological examinations conducted in 2021 were used to diagnose the patient with PSC-AIH-UC overlap syndrome. He was treated with various drugs, including UDCA, methylprednisolone, mycophenolate mofetil, and mesalazine. His liver function improved significantly after treatment and follow-up is ongoing. Our case report highlights the need to raise awareness about rare and difficult-to-diagnose clinical disorders.

Sclerodermic or scleroderma-like lupus erythematosus panniculitis (SLEP) shares both clinical and histopathological features between lupus panniculitis and localized scleroderma. It is exceedingly rare. We herein report a case of SLEP manifested with a solitary, firm-to-hard, erythematous plaque in an Asian woman. This patient responded well to intralesional corticosteroid and antimalarials. We have reviewed the pathogenesis of fibrosis in patients with chronic cutaneous lupus erythematosus as well as documented cases of SLEP in the literature.

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are common diseases that strongly impact the quality and length of life. Their coexistence is determined by overlap syndrome (OS). This systematic review aims to define the significance of these comorbidities according to the current state of knowledge. For this systematic review, we searched PubMed, Scopus, and Cochrane for studies published between 2018 and 26 October 2022, to find original, observational, human studies published in English, where the diagnosis of COPD was according to the Global Initiative for Obstructive Lung Disease guidelines and the diagnosis of OSA was based on polysomnography. The quality of studies was assessed using the Newcastle-Ottawa quality assessment tool for cohort and case-control studies, as well as its modification for cross-sectional studies. Of the 1548 records identified, 38 were eligible and included in this systematic review. The included studies covered a total population of 27,064 participants. This paper summarizes the most important, up-to-date information regarding OS, including the prevalence, meaning of age/gender/body mass index, polysomnography findings, pulmonary function, comorbidities, predicting OSA among COPD patients, and treatment of this syndrome.

Because of some similarities in organ involvement, clinical manifestations, and histopathological features, IgG4-related disease (IgG4-RD) may occur concurrently with some clinicopathologic variants of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). An overlap syndrome of IgG4-RD and AAV has recently been proposed in clinical and/or histopathological studies, indicating that there may be some potential pathophysiological associations between the two disease entities; however, the mechanisms underlying these are incompletely understood. Here, we describe a rare case of a 63-year-old man with IgG4-related tubulointerstitial nephritis (IgG4-TIN) and microscopic polyangiitis-associated glomerulonephritis (MPA-GN) overlap syndrome. The clinical diagnosis of MPA was based on the 2022 American College of Rheumatology (ACR)/European League Against Rheumatology (EULAR) classification criteria. Remission induction therapy with intravenous methylprednisolone was initiated, followed by oral prednisone maintenance therapy with gradual tapering. The patient remained asymptomatic and his renal function was essentially normalized within 3.5 months of follow-up. The serum IgG4 levels decreased to 5 g/L. We also conducted a literature review to identify clinical findings, treatment options, and outcomes of patients with concurrent IgG4-RD and MPA and briefly discussed the potential pathophysiological association between IgG4-RD and MPA. Our findings enrich the database of this rare overlap syndrome and provide a basis for the diagnosis and early intervention in both diseases. These results provide some insights for clinicians to recognize and treat this overlap syndrome.

Anti-OJ antibody is relatively rarely detected in patients with the anti-synthetase syndrome, which is polymyositis (PM)/dermatomyositis (DM) with anti-aminoacyl transfer ribonucleic acid (RNA) synthetase antibodies. There have been few case reports of anti-OJ antibody-positive PM/DM complicated by other connective tissue disorders. Herein, we report the case of a 33-year-old woman who was admitted to our hospital with fever, muscle weakness, and dyspnoea on exertion. She was diagnosed with anti-OJ antibody-positive PM, overlapping systemic lupus erythematosus, and Sjögren\'s syndrome (SS). Her symptoms and clinical findings improved after treatment with prednisolone 1 mg/kg/day without immunosuppressive agents. This is the first case of overlap syndrome with anti-OJ antibody-positive PM, systemic lupus erythematosus, and Sjögren\'s syndrome.

OBJECTIVE: We performed a systematic review and meta-analysis to evaluate the prevalence of concomitant Sjögren\'s syndrome (SS) with primary biliary cholangitis (PBC) in adults and quantify the impact of SS on PBC.
METHODS: PubMed, Web of Science and Cochrane library were searched using subject terms and predefined inclusion and exclusion criteria.
RESULTS: Seventeen articles were included. The prevalence of SS in PBC patients ranged from 3.5 to 73% (35% pooled) (95% CI: 28-41%; p < 0.01). Seven studies included various biochemical indicators, including alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), γ-glutamyltransferase (γ-GT), total bilirubin (TBiL), albumin (ALB) and platelet (PLT), and immunological indexes including IgG, IgM, antinuclear antibody (ANA), anti-mitochondrial antibody (AMA), AMA-M2 and anti-Ro/Sjögren\'s syndrome antigen A (SSA) antibodies. Meta-analysis showed that there were no significant differences in ALT, AST, ALP, γ-GT, TBiL and IgM levels between PBS and PBC with SS. Pooled analysis showed that ALB (MD=0.82; 95% CI: 0.08-1.56) and PLT (MD=30.41; 95% CI: 10.16-50.66) levels were lower, IgG levels (MD=-1.55; 95% CI: -2.39 to -0.72) were higher, and the positive ratios of ANA (RR=0.92; 95% CI: 0.87-0.98), AMA (RR=0.94; 95% CI: 0.89-0.98), AMA-M2 (RR=0.77; 95% CI: 0.70-0.85) and anti-Ro/SSA antibodies (RR=0.29; 95% CI: 0.08-1.01) were significantly higher in PBC patients with SS than in PBC patients.
CONCLUSIONS: Our study confirms that SS is common in PBC. Comorbid SS appears to influence the clinical phenotype of PBC and may therefore influence the management of PBC.

OBJECTIVE: Sjögren\'s syndrome (SS) and ANCA-associated vasculitis (AAV) have distinct clinical presentation and evolution, with paucity of reports on overlap syndrome. We aimed to better characterize this entity.
METHODS: We report four additional cases from the Montpellier university hospital. We also performed a systematic literature review, according to PRISMA guidelines, in Medline, Embase, Web of science, Cochrane Library, and grey literature. Demographic, clinical, and paraclinical data on SS and AAV were analysed.
RESULTS: A total of 3133 articles was identified in databases, with 2695 articles screened for eligibility. After exclusion, we had 30 articles on 40 patients to analyse, in addition to 4 patients from our local recruitment (44 patients overall). Patients were female in 81.8%, with median age at AAV onset of 63.5 years. All patients but one presented with SS before, or concomitantly to the diagnosis of AAV, with a median delay of 12 months between both diagnoses. AAV predominantly had renal involvement (35/44 patients, 79.5%), anti-MPO antibodies being the most frequent (35 patients), even in patients presenting with granulomatosis with polyangiitis. We observed significantly more Raynaud phenomenon and associated auto-immune diseases in the group of non-granulomatous AAV (10 patients versus 1, p = 0.015 and 8 patients versus 0, p = 0.013, respectively).
CONCLUSIONS: This is the largest descriptive study on the association between SS and AAV, providing information on this challenging diagnosis and interplay between these two diseases. Particular attention should be paid in the first months after diagnosis, given the specific complications and outcomes of each disease.

Anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides are infrequent autoimmune diseases characterized by inflammation of the walls of small vessels leading to tissue and endothelial damage. On the other hand, IgG4-related disease is a fibroinflammatory disease characterized histologically by lymphoplasmacytic infiltrates with IgG4+ plasma cells, storiform fibrosis, and obliterative phlebitis that may affect nearly every organ of the body. There are similarities in clinical, serological, radiological, and histopathological features between both diseases, and hence, they usually mimic each other complicating the differential diagnosis. Furthermore, reports of patients with the coexistence of both conditions (overlap syndrome) have been reported. We herein report a patient with an unequivocal diagnosis of ANCA-associated vasculitis, specifically granulomatosis with polyangiitis (posterior uveitis, polyneuropathy, pauci-immune glomerulonephritis with crescent formation and granulomas, and MPO-ANCA positivity) and IgG4-related disease (thoracic aortitis, tubulointerstitial nephritis with prominent IgG4+ plasma cell infiltration, fibrosis, and obliterative arteritis, high levels of serum IgG4, and eosinophilia) overlap syndrome.