• Clinical science

Pheochromocytoma

Summary

A pheochromocytoma is a catecholamine-secreting tumor typically located in the adrenal medulla. Pheochromocytomas are usually benign (∼ 90% of cases) but may also be malignant. Classic clinical features are due to excess sympathetic nervous system stimulation and involve episodic blood pressure crises with paroxysmal headaches, diaphoresis, heart palpitations, and pallor. However, a pheochromocytoma may also present asymptomatically or with persistent hypertension. Elevated catecholamine metabolites in the plasma or urine confirm the diagnosis, while imaging studies in patients with positive biochemistry are used to determine the location of the tumor. Surgical resection is the treatment of choice, but is only carried out once alpha blockade with phenoxybenzamine has become effective.

Epidemiology

  • Age range: 3rd–5th decades of life
  • Present in up to 1% of all hypertensive patients

References:[1]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

“10 percent rule”- roughly 10% of pheochromocytomas are: extra-adrenal, multiple, bilateral, malignant, pediatric cases, not associated with hypertension, show calcifications on imaging!

References:[2][3][4]

Clinical features

Clinical presentation is related to fluctuating levels of excess epinephrine, norepinephrine, and dopamine.

Hypertensive crises can be triggered by palpation of the tumor on abdominal exam!

References:[2][5][6]

Diagnostics

Laboratory tests

Other diagnostic tests

  • 24-hour ambulatory blood pressure monitoring
  • Adrenal/abdominal CT or MRI (after positive biochemistry tests to localize tumor)
    • Scintigraphy (MIBG)
  • Other imaging to search for potential additional tumors in patients with pheochromocytoma and MEN2A, MEN2B, NF1, or VHL

References:[2][1]

Treatment

  • Operable disease: Management consists of preoperative blood pressure management and then surgery.
    • Preoperative blood pressure management: Combined alpha and beta-adrenergic blockade
    • Treatment of choice: laparoscopic tumor resection (adrenalectomy)
      • "No-touch" technique
      • Open surgical resection is reserved for large or invasive tumors.

Starting beta blockers before alpha blockade is contraindicated. Beta blockers cancel out the vasodilatory effect of peripheral beta-2 adrenoceptors, potentially leading to unopposed alpha-adrenoceptor stimulationvasoconstrictionhypertensive crisis.

References:[2][5]

  • 1. National Cancer Institute. Pheochromocytoma and Paraganglioma Treatment (PDQ®)–Health Professional Version. https://www.cancer.gov/types/pheochromocytoma/hp/pheochromocytoma-treatment-pdq#link/_64_toc. Updated July 10, 2015. Accessed February 13, 2017.
  • 2. Kasper DL, Fauci AS, Hauser SL, Longo DL, Lameson JL, Loscalzo J. Harrison's Principles of Internal Medicine. New York, NY: McGraw-Hill Education; 2015.
  • 3. Agabegi SS, Agabegi ED. Step-Up To Medicine. Baltimore, MD, USA: Wolters Kluwer Health; 2015.
  • 4. Blake MA. Pheochromocytoma. In: Griffing GT. Pheochromocytoma. New York, NY: WebMD. https://emedicine.medscape.com/article/124059. Updated October 10, 2017. Accessed January 30, 2018.
  • 5. Le T, Bhushan V, Chen V, King M. First Aid for the USMLE Step 2 CK. McGraw-Hill Education; 2015.
  • 6. Zuber SM, Kantorovich V, Pacak K. Hypertension in Pheochromocytoma: Characteristics and Treatment. Endocrinol Metab Clin North Am. 2011; 40(2): pp. 295–311. doi: 10.1016/j.ecl.2011.02.002.
  • Lenders JW, Eisenhofer G, Mannelli M, Pacak K. Phaeochromocytoma. Lancet. 2005; 366(9486): pp. 665–675. doi: 10.1016/s0140-6736(05)67139-5.
last updated 08/13/2019
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