What is the primary cause of hypertension in extra-adrenal pheochromocytoma?

In extra-adrenal pheochromocytoma, the primary cause of hypertension is the production of catecholamines, particularly pure norepinephrine. These tumors, which arise from chromaffin cells outside of the adrenal glands, typically secrete norepinephrine in large quantities. This leads to sustained vasoconstriction, increased systemic vascular resistance, and consequent elevation in blood pressure.

While extra-adrenal pheochromocytomas may sometimes secrete other catecholamines, the predominant release of norepinephrine is primarily responsible for the hypertension seen in patients. The mechanism involves the activation of alpha-adrenergic receptors, which causes vascular smooth muscle contraction and increases peripheral resistance, thereby raising blood pressure.

Other options involve factors that may influence blood pressure but are not the primary cause in this context. Elevated cortisol levels would pertain more to conditions like Cushing's syndrome, while renin secretion and elevated epinephrine may also play roles in other types of hypertension. However, in the scenario of extra-adrenal pheochromocytoma, it is the excessive secretion of norepinephrine that is central to the hypertensive effect observed in these patients.