Final answer:
A pheochromocytoma is the most common adrenal medullary tumor in adults. It causes excessive production of catecholamines and can lead to hypertension.
Step-by-step explanation:
The most common adrenal medullary tumor in adults is called a pheochromocytoma. These tumors develop in the adrenal medulla, the inner portion of the adrenal glands.
Pheochromocytomas lead to excessive production of catecholamines, which can result in hypertension (high blood pressure). These tumors are relatively rare, but if left untreated, they can cause serious health problems.