• Clinical science

Pheochromocytoma

Summary

A pheochromocytoma is a catecholamine-secreting tumor that typically develops 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, pheochromocytomas may also be asymptomatic or manifest 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-adrenergic blockade with phenoxybenzamine has become effective.

Epidemiology

  • Incidence [1]
    • Most common tumor of the adrenal medulla in adults
    • Present in up to 1% of all hypertensive patients
  • Age: 3rd–5th decades of life [1]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

MAry P. sang “superCALi-fragilistic-EXpiali-DOcious” to the children 10 times: 10% of pheochromocytomas are MAlignant; 10% show CALcifications; 10% are EXtrarenal; 10% are DUal sided, i.e., bilateral; and 10% affect children.

Clinical features

Clinical presentation is related to fluctuating levels of excess epinephrine, norepinephrine, and dopamine secretion, therefore, symptoms are relapsing and remitting (episodic hyperadrenergic syndrome).

5 most important Problems (5 P’s) of Pheochromocytoma: increased blood Pressure, head Pain (headache), Perspiration, Palpitations, and Pallor

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

Diagnostics

Laboratory tests [1]

Whenever possible, all medications should be put on hold one week prior to testing.

Other diagnostic tests [2][1]

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

Differential diagnoses

Pheochromocytoma is often referred to as “the great mimic” because signs and symptoms are similar to those produced by many other clinical conditions. [6]

The differential diagnoses listed here are not exhaustive.

Treatment

Operable disease

Management consists of preoperative blood pressure management and then surgery.

  • Preoperative blood pressure management: combined alpha-adrenergic and beta-adrenergic blockade
    1. First, a non-selective irreversible alpha-blocker is given; : Phenoxybenzamine blocks alpha-1 and alpha-2 adrenoceptors equally and irreversibly [7]
    2. After sufficient alpha-adrenergic blockade, a beta-blocker may be started for additional blood pressure control and control of tachyarrhythmias.
  • Laparoscopic tumor resection (adrenalectomy): treatment of choice
    • No-touch technique
    • Open surgical resection is reserved for large or invasive tumors.
  • Prognosis and follow-up [1]
    • Most patients with benign pheochromocytoma become normotensive after tumor resection. [8]
    • Long-term annual biochemical monitoring for recurrence is indicated in all patients.
    • Benign pheochromocytoma recurs in ∼ 15% of patients, usually 5–15 years after surgery.

Inoperable disease

Treat PHEochromocytoma with PHEnoxybenzamine, but remember that Alpha-blockers should be given Ahead and Beta-blockers Behind.

Starting beta-blockers before alpha-blockers is contraindicated. Beta-blockers cancel out the vasodilatory effect of peripheral beta-2 adrenoceptors, potentially leading to unopposed alpha-adrenoceptor stimulation, causing vasoconstriction and ultimately hypertensive crisis.

  • 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. 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.
  • 4. Vora K, Shah V. Diagnosis of pheochromocytoma. Journal of Anaesthesiology Clinical Pharmacology. 2012; 28(2): p. 274. doi: 10.4103/0970-9185.94931.
  • 5. Guller U, Turek J, Eubanks S, Delong ER, Oertli D, Feldman JM. Detecting Pheochromocytoma. Ann Surg. 2006; 243(1): pp. 102–107. doi: 10.1097/01.sla.0000193833.51108.24.
  • 6. Lenders JW, Eisenhofer G, Mannelli M, Pacak K. Phaeochromocytoma. Lancet. 2005; 366(9486): pp. 665–675. doi: 10.1016/s0140-6736(05)67139-5.
  • 7. Antman EM. Cardiovascular Therapeutics E-Book. Elsevier Health Sciences; 2012.
  • 8. Falhammar H, Kjellman M, Calissendorff J. Treatment and outcomes in pheochromocytomas and paragangliomas: a study of 110 cases from a single center. Endocrine. 2018; 62(3): pp. 566–575. doi: 10.1007/s12020-018-1734-x.
last updated 10/22/2020
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