Phenotype and prognosis of primary sclerosing cholangitis-autoimmune hepatitis variant syndrome.

Diagnose PSC with high-quality MRCP as the reference-standard imaging (avoid ERCP for diagnostic purposes; if MRCP findings are equivocal, repeat MRCP rather than proceeding to ERCP), reserving ERCP for therapeutic intervention, and exclude secondary sclerosing cholangitis/IgG4-related disease. No disease-modifying therapy is proven to alter transplant-free survival, but moderate-dose UDCA (13-23 mg/kg/day) may now be considered and continued in patients not enrolled in or eligible for a clinical trial if it produces a meaningful improvement in alkaline phosphatase (GGT in children) and/or symptoms by 12 months, discontinuing if no response; high-dose UDCA remains contraindicated. Perform annual abdominal MRI/MRCP with or without serum CA19-9 for cholangiocarcinoma/gallbladder-cancer surveillance in adults with large-duct PSC (not recommended under age 18 or in small-duct PSC). Manage gallbladder polyps by size, cholecystectomy for polyps >8 mm, ultrasound surveillance every 6 months for polyps ≤8 mm, rather than referring every polyp. For colorectal surveillance, begin surveillance colonoscopy at the time of PSC-IBD diagnosis (or at age 15 for childhood-onset disease) and repeat at 1-2 year intervals; in PSC without IBD, perform a diagnostic colonoscopy at PSC diagnosis and repeat every 5 years if IBD is not found. Evaluate dominant strictures with brush cytology plus FISH (± cholangioscopy) before/at balloon dilation, repeating ERCP with sampling in 3 months if cytology is suspicious regardless of FISH result. Treat recurrent cholangitis and cholestatic pruritus, maintain bone health, and refer for transplant evaluation for decompensation, intractable pruritus, recurrent bacterial cholangitis, or early-stage CCA per Mayo protocol.