Soru

A 48-year-old woman undergoes a percutaneous liver biopsy to evaluate persistently abnormal liver biochemistries. Over the past year, she has experienced worsening fatigue and generalized pruritus. Her medical history is notable only for hypothyroidism managed with levothyroxine. Laboratory evaluation shows an alkaline phosphatase of 410 U/L, aspartate aminotransferase of 55 U/L, and alanine aminotransferase of 62 U/L. Total bilirubin is 1.0 mg/dL. An abdominal ultrasound demonstrates a homogeneous liver echotexture with no intrahepatic or extrahepatic biliary dilatation. The liver biopsy specimen reveals expanded portal tracts with a dense lymphoplasmacytic infiltrate and scattered eosinophils. The inflammatory cells are centered around small interlobular bile ducts, demonstrating epithelial cell swelling, vacuolization, and disruption of the ductal basement membrane. Several poorly formed, noncaseating granulomas are intimately associated with these damaged ducts. The surrounding hepatic lobules are largely preserved. Based on these histopathologic findings, which of the following is the most definitive diagnosis?