Pheochromocytoma most frequently arises from the adrenal medulla. However, about 10% of the masses are extra-adrenal and can be found along the sympathetic chain in the urinary bladder and organ of Zuckerkandl.

It is may not possible to distinguish malignant from benign pheochromocytomas merely on the direct appearance of the mass. However, direct tumor invasion into adjacent structures or the presence of metastases suggests a malignant lesion.