Case 2

A 28-year-old African-American man presents to the physician with fever, weight loss, and abdominal pain. His blood pressure is 168/92mm Hg, his pulse is 83/min, and his respiratory rate is 18/min. On physical examination, there is palpable purpura on his lower extremities; a fundoscopic examination reveals fluffy, white spots on his retina. His past medical history is significant for a previous hepatitis B infection. An arterial biopsy is shown in the image. Which of the following is the most prominent morphologic feature of the affected arteries in this patient’s disease process? *  A- Caseating necrosis B- Eosinophilic infiltrate C- Fibrinoid necrosis D- Granulomatous infl ammation E- Langhans’ giant cells F- Onion skinning