Pheochromocytoma

Pheochromocytoma is a rare catecholamine-secreting tumor arising from chromaffin cells of the adrenal medulla, leading to episodic or sustained hypertension and multisystem manifestations.

Definition

Pheochromocytoma is a rare catecholamine-secreting tumor arising from chromaffin cells of the adrenal medulla, leading to episodic or sustained hypertension and multisystem manifestations.

Epidemiology

Incidence: 2–8 per million per year
Accounts for <0.1% of hypertension cases
Peak age: 30–50 years, but can occur at any age
Equal sex distribution
10% rule historically: 10% bilateral, 10% malignant, 10% extra-adrenal, 10% familial (now higher with genetic testing)

Etiology

Sporadic: most common
Familial/genetic syndromes: Multiple Endocrine Neoplasia type 2 (MEN2), Von Hippel-Lindau (VHL), Neurofibromatosis type 1 (NF1), Succinate dehydrogenase (SDH) mutations
Extra-adrenal paragangliomas (chromaffin tissue outside adrenal medulla)

Pathophysiology

Tumor arises from adrenal medulla chromaffin cells or sympathetic paraganglia
Excess catecholamine (epinephrine, norepinephrine, dopamine) secretion → hypertension, tachycardia, hyperglycemia, sweating, and other adrenergic symptoms
Paroxysmal or sustained catecholamine release leads to episodic symptoms
Catecholamine-induced vascular changes can cause cardiomyopathy and end-organ damage