Pheochromocytoma and Paraganglioma Treatment (PDQ®): Treatment - Health Professional Information [NCI] - General Information About Pheochromocytoma and Paraganglioma
Table 1. Major Genetic Syndromes That Carry an Increased Risk of Pheochromocytoma continued...
Pheochromocytomas and extra-adrenal paragangliomas can also occur in the following two other very rare syndromes:
- The Carney triad of extra-adrenal paraganglioma, gastrointestinal stromal tumor (GIST), and pulmonary chondroma.
- The Carney-Stratakis dyad of paraganglioma and GIST.
Other genetic causes of pheochromocytoma and paraganglioma are being studied. For example, truncating germline mutations in the transmembrane-encoding gene TMEM127 on chromosome 2q11 have been shown to be present in approximately 30% of affected patients with familial disease and in about 3% of patients with apparently sporadic pheochromocytomas without a known genetic cause.TMEM127 is a negative regulator of mammalian target of rapamycin (mTOR) effector proteins.
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.