Definition
A.A catecholamine-secreting tumor that typically produces one or more of the following hormones: Epinephrine, norepinephrine, or dopamine.
B.Cardiovascular morbidity and mortality may be high for undiagnosed pheochromocytomas (PCCs) due to catecholamine secretion.
C.PCCs enlarge over time and may cause mass effect if undiagnosed.
Incidence
A.0.2% to 0.6% of patients in an outpatient setting with hypertension have a PCC.
B.Autopsy studies suggest that 0.05% to 1% of patients have undiagnosed PCCs.
C.Peak incidence is between the fourth and fifth decades of life.
D.Approximately 5% of adrenal incidentalomas are PCCs and 10% to 17% of PCCs may be malignant.
E.PCC should be considered in the workup for malignant hypertension, particularly when the patient reports paroxysmal symptoms, has an adrenal incidentaloma, or has a hereditary predisposition to PCC.
Pathogenesis
A.Catecholamine-producing neuroendocrine tumors arising from the adrenomedullary chromaffin cells.
B.Germline mutations: Present in at least one-third of patients presenting with PCC.
C.PCCs may be related to a hereditary condition.
Predisposing Factors
A.30% of patients have a PCC as part of a genetic disorder.
B.Several genetic conditions predispose patients to PCC, including:
1.Multiple endocrine neoplasia (MEN) type 2A.
2.MEN type 2B.
3.Von Hippel–Lindau syndrome.
4.Neurofibromatosis type 1.
Subjective Data
A.Common complaints/symptoms.
1.Signs and symptoms are present in about 50% of patients.
2.Symptoms are typically paroxysmal.
3.Classic triad of symptoms includes:
a.Headache.
b.Sweating.
c.Tachycardia.
B.Other signs and symptoms.
1.Cardiovascular (palpitations).
2.Anxiety/panic attacks.
3.Nausea.
4.Abdominal/chest pain.
5.Flushing.
6.Weight loss.
7.Weakness.
8.Tremor.
9.Pallor.
10.Shortness of breath.
Physical Examination
A.Vital signs.
1.Tachycardia.
2.Hypertension.
3.Weight loss.
B.Complete cardiovascular examination.
C.Skin examination.
1.Pallor.
2.Flushing.
Diagnostic Tests
A.Testing for PCC is necessary if there is:
1.Previous history of PCC.
2.Symptoms of PCC, especially if they occur in a paroxysmal manner.
3.Adrenal incidentaloma.
4.Hereditary predisposition to PCC.
B.Initial testing involves two types of metanephrine tests.
1.Urinary fractionated metanephrines should be a 24-hour urine collection and include a creatinine level.
2.Plasma-free metanephrines should be drawn with the patient in the supine position.
a.Sympathetic activation occurs in the upright position and can falsely elevate catecholamine levels.
b.Ideally, patients should be in the supine position for 30 minutes prior to blood draw.
C.False positive results are common.
1.Physiologic stress such as hospitalization may elevate hormones and should be considered contributing factors to elevations.
2.Multiple drugs can cause false positive results, including:
a.Acetaminophen.
b.Beta-blockers: Labetalol, sotalol.
c.Tricyclic antidepressants.
d.Sympathomimetics.
e.Buspirone.
f.Monoamine oxidase (MAO) inhibitors.
g.Cocaine.
3.Confirmatory testing is needed if positive results are believed to be influenced by any of these
factors.
D.When biochemical results suggest a PCC, imaging is necessary. A CT scan should be ordered to locate the mass (CT preferred over MRI).
E.An MRI should be used in patients when a CT scan cannot be performed (e.g., allergy to CT contrast, or when attempting to limit radiation, such as in pregnant women).
F.All patients with PCCs should consider genetic testing to assess for other related conditions such as the MEN syndromes.
Differential Diagnosis
A.Labile essential hypertension.
B.Malignant hypertension.
C.Illegal drug use such as phencyclidine or cocaine.
D.Combining multiple pharmacologic agents such as MAO inhibitors, decongestants, or sympathomimetics.
E.Stroke.
F.Myocardial infarction.
G.Anxiety disorder.
H.Hyperthyroidism.
I.Hypoglycemia (including insulinoma).
J.Alcohol withdrawal.
Evaluation and Management Plan
A.General plan. Treatment involves surgery.
1.Preoperative management.
a.Preoperative medical treatment should occur for 7 to 14 days if possible to stabilize blood pressure (BP) and heart rate.
b.Patients with hormonally active PCCs should undergo preoperative blockage with an a-adrenergic receptor blocker such as phenoxybenzamine or doxazosin. Calcium channel blockers can be used as secondary agents for further BP control.
c.Beta-blockers can be added after initiation of an a-adrenergic receptor blocker to control heart rate. They should not be added before a-adrenergic receptor blockers due to the potential for hypertensive crisis if the a-adrenergic receptors are unopposed.
d.a-Methyl-paratyrosine (metyrosine) can be used for a short time preoperatively in combination with an a-adrenergic receptor blocker to further stabilize BP and reduce blood loss and volume depletion during surgery.
e.Initiating a continuous saline infusion the evening before surgery is another helpful approach to minimize volume depletion.
f.Preoperative diet should include high sodium and high fluid intake to prevent hypotension after the tumor removal.
g.Monitor heart rate, BP, and blood glucose in the pre- and postoperative periods.
2.Operative procedure.
a.Most PCCs can be removed via minimally invasive adrenalectomy.
b.Open resection is recommended for large tumors greater than 6 cm or for invasive tumors.
3.Postoperative management.
a.The most common postoperative complications include hypertension, hypotension, and rebound hypoglycemia.
b.Heart rate, BP, and glucose should be monitored for 24 to 48 hours.
c.For patients who are at risk for adrenal insufficiency (AI) after surgery, particular attention should be paid to signs and symptoms of AI.
B.Patient/family teaching points.
1.Consider genetic testing, if not already completed, for other potential family members at risk.
C.Discharge instructions (if standard accepted guidelines exist please use discharge template).
1.Monitor BP at home, counseling particularly on the potential for low or labile BP.
2.Monitor postoperative incision for any signs of infection.
3.Discuss the symptoms of PCC and the recommendation for annual biochemical monitoring to ensure long-term disease remission.
Follow-Up
A.Biochemical testing should be repeated 2 to 4 weeks after surgery to ensure complete tumor resection.
B.Annual biochemical monitoring is recommended to assess for recurrent disease.
Consultation/Referral
A.Consultation with an endocrinologist and an endocrine surgeon is preferred for optimal patient outcomes.
B.It is recommended that patients with PCCs be treated by multidisciplinary teams at centers with expertise in this condition. Some studies suggest that there is lower postoperative mortality and shorter hospital stays in high-volume centers, but these data are not conclusive.
Special/Geriatric Considerations
A.Patients with metastatic disease or general complexity should always be referred to high-volume centers with expertise in the management of PCCs.
Bibliography
Lenders, J. W., Duh, Q.-Y., Eisenhofer, G., Gimenez-Roqueplo, A.-P., Grebe, S. K., Murad, M. H., … Young, W. F., Jr. (2014). Pheochromocytoma and paraganglioma: An endocrine society clinical practice guideline. Journal of Clinical Endocrinology & Metabolism, 99(6), 1915–1942. doi:10.1210/jc.2014-1498
Young, W. F., Jr. (2018, December 11). Clinical presentation and diagnosis of pheochromocytoma. In K. A. Martin (Ed.), UpToDate. Retrieved from https://www.uptodate.com/contents/clinical-presentation-and-diagnosis-of-pheochromocytoma