From Landsberg L, Young JB. Catecholamines and the adrenal medulla. In Wilson JD, Foster DW, eds. Williams Textbook of Endocrinology. 9th ed. Philadelphia: Saunders; 1998:707.
Locations of Extraadrenal Pheochromocytomas
| Location | % |
| Cervical | 2 |
| Thoracic | 10–20 |
| Intraabdominal | 70–80 |
| Upper abdomen | 40 |
| Organ of Zuckerkandl | 30 |
| Bladder | 15 |
From Landsberg L, Young JB. Catecholamines and the adrenal medulla. In Wilson JD, Foster DW, eds. Williams Textbook of Endocrinology. 9th ed. Philadelphia: Saunders; 1998:707.
Diagnostic tests for determining the presence of a catecholamine tumor include measurements of urinary or plasma catecholamines and their metabolites, vanillylmandelic acid, and metanephrines. Free norepinephrine measurement in a 24-hour urine sample is a sensitive index of pheochromocytoma (see the table below). Other methods that can be used to assess for the presence of a pheochromocytoma include a clonidine suppression test, CT scan, and metaiodobenzylguanidine (MIBG) scintigraphy.
Values for Catecholamines and Catecholamine Metabolites
| Hormone or Metabolite | Reference Range |
| Vanillylmandelic acid, urine | 2.0–7.0 mg/24 hr |
| Metanephrines, urine | <1.3 mg/24 hr |
| Norepinephrine, urine | <100 mcg/24 hr |
| Norepinephrine, plasma | 150–450 pg/mL |
| Epinephrine, plasma | <35 pg/mL |
| Catecholamines, free urinary | <110 mcg/24 hr |
Incidence and prevalence
Pheochromocytomas are rare, occurring in approximately 0.1% of hypertensive patients. These tumors may be associated with neurocutaneous syndromes such as von Hippel-Lindau disease, tuberous sclerosis, and Sturge-Weber syndrome. The tumors may also be a component of MEN type 2A or 2B (see the table below). Patients with a family history of MEN syndrome should be regularly screened for pheochromocytoma. Twenty-five percent of pheochromocytomas occur as part of an inherited autosomal dominant trait.
Manifestations of Multiple Endocrine Neoplasia
| Syndrome | Manifestations |
| MEN type 1 (Wermer’s syndrome) | Hyperparathyroidism, pituitary adenomas, pancreatic islet cell tumors |
| MEN type 2A (Sipple’s syndrome) | Medullary thyroid cancer, hyperparathyroidism, pheochromocytoma |
| MEN type 2B (mucosal neuroma syndrome) | Medullary thyroid tumor, pheochromocytoma, neuromas of the oral mucosa, marfanoid habitus |
Pheochromocytomas can occur at any age but usually occur within the third to the fifth decades of life, with equal frequency in both sexes in adults.
Clinical manifestations
Manifestations of a pheochromocytoma reflect massive catecholamine release and include hypertension, diaphoresis, headache, tremors, and palpitations. Hypertension may be paroxysmal or sustained. The combination of paroxysmal diaphoresis, tachycardia, and headache in hypertensive patients is a recognized triad of symptoms for pheochromocytoma.
A catecholamine-mediated paroxysm typically consists of a sudden and alarming increase in blood pressure, a severe throbbing headache, profuse sweating, palpitations, tachycardia, a sense of doom, anxiety, pallor (rarely flushing), and nausea. Orthostatic hypotension may result from plasma volume deficit or a lack of tone in the postural reflexes that defend upright blood pressure caused by the sustained excesses of catecholamines. Paroxysmal symptoms may last several minutes to days and are often followed by physical exhaustion. The frequencies of clinical symptoms associated with pheochromocytoma are outlined in the table below.
Frequency of Symptoms in 100 Patients with Pheochromocytoma
| Symptom | % |
| Headache | 80 |
| Excessive perspiration | 71 |
| Palpitation (with or without tachycardia) | 64 |
| Pallor | 42 |
| Nausea (with or without vomiting) | 42 |
| Tremor or trembling | 31 |
| Weakness or exhaustion | 28 |
| Nervousness or anxiety | 22 |
| Epigastric pain | 22 |
| Chest pain | 19 |
| Dyspnea | 19 |
| Flushing or warmth | 18 |
| Numbness or paresthesia | 11 |
| Blurring of vision | 11 |
| Tightness of throat | 8 |
| Dizziness or faintness | 8 |
| Convulsions | 5 |
| Neck or shoulder pain | 5 |
| Extremity pain | 4 |
| Flank pain | 4 |
From Landsberg L, Young JB. Catecholamines and the adrenal medulla. In Wilson JD, Foster DW, eds. Williams Textbook of Endocrinology. 9th ed. Philadelphia: Saunders; 1998:706.
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