Pheochromocytoma is a tumour of the:
Most adrenal medullary tumors (pheochromocytomas) secrete norepinephrine or epinephrine or both and produce sustained hypertension.
Pheochromocytoma is a tumour of the adrenal medulla.
Reference: Ganong’s Review of Medical Physiology T W E N T Y - F I F T H   E D I T I O N page no 356
Adrenal cortex
Parathyroids
Pituitary
None of the above