Case Presentation

A 68-year-old patient with a history of chronic kidney disease and kidney transplantation was referred to a Gastroenterology consultation for evaluation of intra- hepatic bile ducts dilatation revealed in abdominal ultrasound (US). Laboratory results did not reveal significant changes on liver tests. Abdominal computed tomography was initially performed followed by magnetic resonance. What is the diagnosis and the most probable etiology?(Figs. 1 and 2)

Figure 1: Axial and coronal soft tissue window, 3mm slice thickness, contrast-enhanced CT.  

Figure 2: Axial and coronal T2-weighted TSE.