<prompt> Percentage of pheochromocytoma that are bilateral is:11-51025  <response>: Pheochromocytomas often are called the 10 percent tumor because 10 are bilateral, 10 are malignant, 10 occur in pediatric patients, 10 are extra-adrenal, and 10 are familial. Ref: Schwazs principle of surgery 9th edition, chapter 38. 