This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Which of the following criteria can be used to determine if a pheochromocytoma lesion is benign or malignant \nSelect and explain. \nA. Blood vessel invasion, B. Cannot be determined by microscopic examination, C. Hemorrhagic and necrosis, D. Nuclear pleomorphism', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ref Robbins 8/e p1159-1161;9/e p1135 Pheochromocytoma and their related counterpas in extra adrenal sites called paraganglioma, are notorious Because the only reliable indicator of metastasis potential is the presence of distant metastasis . Very malignant appearing tumors may not metastasize and benign appearing tumors may produces metastases . These tumors should all be considered " potentially malignant" .', 'role': 'assistant'}]