All of the given options are true about pheochromocytoma. The primary clinical symptoms of pheochromocytoma relate to the excess catecholamine, and the primary symptom associated with this tumor is hypeension. Pheochromocytomas may be intraadrenal, extraadrenal, benign, or malignant. But, only 10% Pheochromocytoma are malignant and hence it is the best possible answer. The classic "P" signs and symptoms of pheochromocytoma include paroxysms, perspiration, pallor, pressure (hypeension), palpitations (tachycardia), and pounding headaches. Note - A classic teaching point for describing the natural history of pheochromocytomas is "The Rule of Tens." This rule states that 10% of pheochromocytomas are malignant, 10% are bilateral, 10% are familial, and 10% are extra-adrenal. Ref: DeVita, Hellman, and Rosenberg's Cancer, Volume 1 By Vincent T DeVita, Jr M.D., Theodore S. Lawrence, Steven A Rosenberg, M.D., 2008, Page 1698; Harrison's Internal Medicine, Chapter 337. Pheochromocytoma Table 337-1.