Table 1. Major Genetic Syndromes That Carry an Increased Risk of Pheochromocytoma continued...
In patients with a unilateral pheochromocytoma and no personal or family history suggestive of hereditary disease, genetic testing can be considered if patients are between the ages of 40 years and 50 years, but genetic testing is generally not recommended if patients are older than 50 years. If a mutation is identified, predictive genetic testing should be offered to asymptomatic at-risk family members. (Refer to the PDQ summary on the Genetics of Medullary Thyroid Cancer for more information.)
Patients with pheochromocytomas and sympathetic extra-adrenal paragangliomas may present with symptoms of excess catecholamine production, including the following:
These symptoms are often paroxysmal, although sustained hypertension between paroxysmal episodes occurs in 50% to 60% of patients with pheochromocytoma. Episodes of hypertension can be variable in frequency, severity, and duration and are often extremely difficult to manage medically. Hypertensive crisis can lead to cardiac arrhythmias, myocardial infarction, and even death.
Patients are often very symptomatic from excess catecholamine secretion. Symptoms of catecholamine excess can be spontaneous or induced by a variety of events, including the following:
- Strenuous physical exertion.
- Labor and delivery.
- Anesthesia induction.
- Surgery or other invasive procedures, including direct instrumentation of the tumor (e.g., fine-needle aspiration).
- Foods high in tyramine (e.g., red wine, chocolate, and cheese).
- Urination (e.g., bladder wall tumor, which is rare).
Phenoxybenzamine (blocks alpha receptors) is an effective treatment for catecholamine excess and metyrosine (blocks catecholamine synthesis) can be added if needed.
Parasympathetic extra-adrenal paragangliomas do not secrete catecholamines and usually present as a neck mass with symptoms related to compression or are incidentally discovered on an imaging study performed for an unrelated reason. In addition, approximately half of patients with pheochromocytoma are asymptomatic because their neoplasms are discovered in the presymptomatic state by either abdominal imaging for other reasons (e.g., adrenal incidentalomas) or genetic testing in at-risk family members.[21,22,23,24]
The diagnosis of pheochromocytoma is usually suspected by the presence of an adrenal mass or a workup. Biochemical testing is done to document excess catecholamine secretion. Once the biochemical diagnosis of a catecholamine-secreting tumor is confirmed, localization studies should be performed. Controversy exists as to the optimal single test to make the diagnosis.