A 40-year-old woman complains of having severe back pain for about 3 months and recurrent fever. Her past medical history is significant for ulcerative colitis. On physical examination, the patient is thin and jaundiced. The liver edge descends 1 cm below the right costal margin and is nontender. Laboratory studies show normal serum levels of AST and ALT but elevated serum levels of alkaline phosphatase (420 U/L). Endoscopic retrograde cholangiopancreatography demonstrates a beaded appearance of the extrahepatic biliary tree. Which of the following diseases is a late complication of this patient's condition?

Primary sclerosing cholangitis (PSC) is characterized by inflammation and obliterative fibrosis of intrahepatic and extrahepatic bile ducts, with dilation of preserved segments. Approximately 70% of patients with PSC have longstanding ulcerative colitis, although the prevalence of PSC in such patients is only 4%. PSC tends to occur in the third through fifth decades of life, with a significant male predominance (2:1). The clinicopathologic findings are complemented by a characteristic radiographic appearance of a beaded biliary tree, representing sporadic strictures. Cholangiocarcinoma is a late complication of PSC. The other choices are not complications of PSC.Diagnosis: Primary sclerosing cholangitis