This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Malignancy in pheochromocytoma is indicated by- \nSelect and explain. \nA. Vascular invasion, B. Mitotic figures, C. Capsular invasion, D. metastasis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: "Because malignant and benign pheochromocytomas may have an identical histological appearance, the only absolute criterion of malignancy is metastasis"\n\u200b"The diagnosis of malignant pheochromocytoma is made only when metastasis is demonstrated"', 'role': 'assistant'}]