Introduction
Pheochromocytomas are neoplasms of the chromaffin cells of the adrenal medulla or paraganglial cells of extramedullary sites (paragangliomas)
-These tumors secrete excessive amounts of epinephrine, norepinephrine, or both or even dopamine
-Most pheochromocytomas secrete norepinephrine
-Pheochromocytoma was classically referred to as the “tumor of tens” because it was considered that 10% are hereditary, 10% are malignant, 10% are asymptomatic, 10% are extra-adrenal, 10% are extra-abdominal,10% are multiple, 10% are bilateral
– They can occur at any age, have no gender predilection
-Peak incidence: in the fourth and fifth decades of life
-Familial causes: Multiple Endocrine Neoplasia type 2 (MEN 2), von Hippel-Lindau disease, von Recklinghausen neurofibromatosis type 1 (NF-1)
Symptoms & Signs
-The classic pentad of symptoms: Episodic headache, palpitations, unusual sweating, pallor and orthostasis
-Other symptoms: Anxiety, irritability, flushing, chest pain, shortness of breath, nausea, vomiting, abdominal pain
-The most common clinical sign: Hypertension
-Typical paroxysm: Sudden headache, palpitations, and sweating produced by anxiety or activities that compress the tumor (bending, defecation, deep palpation of the abdomen etc)
Diagnosis
24-hour urinary tests: Catecholamines, Fractionated metanephrines, total metanephrines
Plasma tests: Catecholamines, Free metanephrines
Imaging: CT, MRI, MIBG scintigraphy, Somatostatin receptor scintigraphy
Most sensitive test: Plasma fractionated free metanephrines
Most specific test: Urinary total metanephrines
Treatment
Definitive treatment: Surgery
First administer alpha blockers, then beta blockers
α-blockers: Phenoxybenzamine, prazosin, terazosin, doxazosin
beta blockers: Propranolol, atenolol, metoprolol, carvedilol, bisoprolol, esmolol
Calcium channel blockers: Nicardipine