All are true about pheochromocytoma except:

Only 10% are malignant. They are also called 10 % tumors because 10% are bilateral, 10% are extra adrenal, 10% occur in pediatric patients, 10% are familial. One "traditional" 10% rule that has now been modified peains to familial cases. It is now recognized that as many as 25% of individuals with pheochromocytomas and paragangliomas harbor a germline mutation in one of at least six known genes