<prompt> What percentage of pheochromocytomas are malignant?5102015  <response>: b. 10Ref: Nelsons 20e p 2227-2729, Ghai 8e p 525Mnemonic:Rule of ten for Pheochromocytoma: BG MEN: 10 of Pheochromocytoma are: Bilateral Malignant Extra-adrenal: paragangliomas Normotensive No hypertensionNote: 10 of sporadic Pheochromocytoma are bilateral; but 50 of familial tumors are bilateral. 