This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pathology
[{'content': 'In PAN, cysts are seen in all except \nSelect and explain. \nA. Lung, B. Pancreas, C. Liver, D. Hea', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Polyaeritis nodosa (PAN) is a systemic vasculitis of small or medium-sized muscular aeries that typically involves the renal and visceral vessels and spares the pulmonary circulation. Classic PAN is a segmental transmural necrotizing inflammation of small to medium-sized aeries, often with superimposed thrombosis. Kidney, hea, liver, and gastrointestinal tract vessels are affected in descending order of frequency. Robbins Basic pathology,9th edition,pg no.352', 'role': 'assistant'}]