Review Question - QID 213179

A 57-year-old man comes to the clinic for diffuse itchiness and headaches for the past month. He reports that the symptoms began shortly after returning from a camping trip in New Hampshire and are especially worse after he showers. He denies any fever, rashes, chest pain, or shortness of breath but reports a 10-lb. weight loss he attributes to exercise intermittent blurred vision, and mild right upper quadrant (RUQ) pain. His past medical history is significant for hepatitis C infection and hypertension for which he was recently started on lisinopril. A physical examination is unremarkable except for mild RUQ tenderness with a negative Murphy test. A computed tomographic (CT) image of the abdomen is obtained and its results are shown in Figure A. What is the most likely explanation for this patient’s presenting symptoms?