General Information About Pheochromocytoma and Paraganglioma
Table 1. Major Genetic Syndromes That Carry an Increased Risk of Pheochromocytoma continued...
Genetic counseling and testing
It has been proposed that all patients diagnosed with a pheochromocytoma or paraganglioma should consider genetic testing because the incidence of a hereditary syndrome in apparently sporadic cases is as high as 25%.[8,9,19] Early identification of a hereditary syndrome allows for early screening for other associated tumors and identification of family members who are at risk. In addition, some patients with a hereditary syndrome are more likely to develop multifocal, malignant, or recurrent disease. Knowledge of the specific genetic mutation permits increased vigilance during preoperative localization or postoperative surveillance of such patients.
Certain subgroups of patients are at very low risk of having an inherited syndrome (e.g., <2% in patients diagnosed with apparently sporadic pheochromocytoma after age 50 years). Therefore, genetic testing for all patients diagnosed with a pheochromocytoma or paraganglioma may not be practical or cost effective from a population standpoint. It is currently recommended that every patient diagnosed with a pheochromocytoma or extra-adrenal paraganglioma should first undergo risk evaluation for a hereditary syndrome by a certified genetic counselor. (Refer to the NCI Cancer Genetics Services Directory for a list of genetic healthcare professionals.)
Genetic testing is often recommended in the following situations:
- Patients with a personal or family history of clinical features suggestive of a hereditary pheochromocytoma-paraganglioma syndrome.
- Patients with bilateral or multifocal tumors.
- Patients with sympathetic or malignant extra-adrenal paragangliomas.
- Patients diagnosed before age 40 years.
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:
- Forceful palpitations.
- Facial pallor.
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).