This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney and ureter, Subject name: Surgery
[{'content': 'All are features of hypernephroma except: \nSelect and explain. \nA. May invade renal vein, B. Lower pole involvement, C. More common in males, D. Cannon ball secondaries are seen', 'role': 'user'}, {'content': "Answer: B \nExplanation: RENAL CELL CARCINOMA (AKA gravitz tumor, hypernephroma, internist's tumor, radiologist's tumor) - More common in males, in 6th and 7th decade - Tumor usually involve upper pole Most common site of distant metastasis are lungs (cannon ball deposits and pulsatile osteolytic secondaries in bone>liver>brain) Characteristic feature of RCC is tendency to invade renal vein", 'role': 'assistant'}]