Sjögren’s Disease With Primary Biliary Cholangitis Fulfilling the 2010 ACR/EULAR Classification Criteria for Rheumatoid Arthritis: A Case Report and Review of an Under-Recognized Overlap

Sjögren's disease (SjD) and primary biliary cholangitis (PBC) are chronic autoimmune epithelitides that target exocrine glands and small intrahepatic bile ducts, respectively.Their coexistence is well described; less appreciated is a specific and avoidable failure mode.Because rheumatoid factor (RF) positivity, symmetric small-joint involvement and elevated acute-phase reactants are all common in SjD, patients with SjD-associated polyarthritis may reach the six-point threshold of the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for rheumatoid arthritis (RA); those criteria remain valid only if their mandatory exclusion clause is applied.We report a 49-year-old woman who carried a three-year diagnosis of RF-positive, anti-citrullinated peptide antibody (ACPA)-negative RA and had been treated with methotrexate and tofacitinib without ever developing radiographic erosions.Cholestatic liver injury during a course of amoxicillin-clavulanate led to the detection of anti-mitochondrial M2 antibodies and to a liver biopsy showing florid duct lesions with periductal granulomas, establishing stage 1 PBC.Directed questioning subsequently revealed a three-year history of previously unreported sicca symptoms.Anti-Sjögren's-syndrome-related antigen A autoantibodies (anti-Ro/SSA) were positive, the Schirmer test measured 1 mm bilaterally, and minor salivary gland biopsy demonstrated focal lymphocytic sialadenitis with a focus score of 2. These findings yielded a total of 7/9 points according to the 2016 ACR/EULAR classification criteria for SjD, with relevant exclusion criteria assessed and found to be absent.Immunosuppression was withdrawn, followed by sustained biochemical and articular improvement over 24 months after initiation of ursodeoxycholic acid and hydroxychloroquine.We review the epidemiology, shared immunopathogenesis, and therapeutic implications of the SjD-PBC overlap, and propose that, in an appropriate clinical context, a structured inquiry into sicca symptoms and consideration of anti-Ro/SSA testing may be useful in patients with ACPA-negative, RF-positive, non-erosive polyarthritis before escalation to biologic or targeted synthetic therapy.