Immunoglobulin G4-related autoimmune hepatitis with overlapping multiple autoimmune diseases: A case report.

RATIONALE: The prevalence of autoimmune liver disease in Sjogren syndrome (SS) ranges from 1.7% to 47%. Hematologic involvement is commonly observed in SS patients, with 1.5% of patients presenting with monoclonal gammopathy of undetermined significance (MGUS). Chronic antigenic stimulation of B lymphocytes in autoimmune diseases may eventually lead to clonal proliferation or MGUS. Nevertheless, studies reporting the concurrent manifestation of IgG4-related autoimmune hepatitis (IgG4-AIH), Primary biliary cholangitis (PBC), SS, and MGUS are scarce. PATIENT CONCERNS: This article reports a rare case involving the overlap of multiple autoimmune diseases. A middle-aged female patient experienced fatigue, anorexia, xerostomia, jaundice, and pruritus, as well as elevated levels of liver enzymes, globulin, and monoclonal immunoglobulin (M protein). DIAGNOSES: Based on the findings of serum IgG4 levels, autoimmune serology, liver and labial gland biopsy, and bone marrow puncture, a diagnosis of IgG4-AIH, PBC, SS, and MGUS was made. INTERVENTIONS: The patient was initiated on oral prednisone 40 mg once daily and ursodeoxycholic acid capsules 250 mg 3 times daily. Upon stabilization of the condition, prednisone was progressively tapered to a maintenance dose of 5 mg daily. OUTCOMES: Over the 6-month follow-up period, favorable improvements were noted in the patient's symptoms. LESSONS: The purpose of this report's research is to thoroughly describe the clinical manifestations, diagnostic challenges, and treatment difficulties associated with the rare co-existence of multiple autoimmune diseases and hematological diseases, and to summarize the management methods. The significance of this study lies in emphasizing the importance of screening for autoimmune diseases and hematological diseases in patients presenting similar symptoms in clinical practice, aiming to provide a reference for clinicians in identifying and managing such complex cases, thereby enhancing the understanding and treatment level of these diseases.