What percentage of pheochromocytomas are malignant?: (A) 5, (B) 10, (C) 20, (D) 15
Answer is B. b. 10(Ref: Nelson's 20/e p 2227-2729, Ghai 8/e p 525)Mnemonic:'Rule of ten' for Pheochromocytoma: ("BG MEN"): 10% of Pheochromocytoma are:* Bilateral* Malignant* Extra-adrenal: paragangliomas* Normotensive (No hypertension)Note: 10% of sporadic Pheochromocytoma are bilateral; but 50% of familial tumors are bilateral.