A 40-year-old woman presents with progressive jaundice, pruritus, and elevated ALP (3x normal) with near-normal ALT/AST. ANA and anti-smooth muscle antibodies are negative. Serum AMA (anti-mitochondrial antibodies, specifically anti-M2) are strongly positive (titer 1:320). Liver biopsy shows lymphocytic infiltration and granulomatous destruction of small intrahepatic bile ducts. The diagnosis is:
- A Primary biliary cholangitis (PBC) ✓
- B Primary sclerosing cholangitis
- C Autoimmune hepatitis, type 1
- D IgG4-related sclerosing cholangitis
Explanation
Primary biliary cholangitis (formerly primary biliary cirrhosis) is an autoimmune cholestatic liver disease affecting predominantly middle-aged women. The pathognomonic finding is AMA-M2 antibodies (anti-pyruvate dehydrogenase complex E2 subunit, titer >1:40) present in >90% of patients. Liver biopsy shows florid duct lesion — lymphoplasmacytic and granulomatous destruction of small interlobular bile ducts. PSC shows fibro-obliterative cholangitis of large bile ducts (beaded appearance on MRCP) and is associated with IBD; AMA is negative. IgG4-related cholangitis shows elevated IgG4+ plasma cells.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.