Ahead of Rare Disease Day, here is what you need to know about pheochromocytoma and paraganglioma, two rare types of tumors.
Ahead of Rare Disease Day, here is what you need to know about two rare tumor types: pheochromocytoma, a neuroendocrine tumor, and paraganglioma, which forms in a group of nerve cells in the nervous system.
In pheochromocytoma, the tumor originates from chromaffin cells in the inside portion of the adrenal gland (a small gland that makes steroid hormones like adrenaline, and noradrenaline). A neuroendocrine tumor is one that forms from cells that release hormones into the blood in response to a signal from the nervous system and may make higher-than-normal amounts of hormones.
Paraganglioma, which are closely related to pheochromocytoma, allows the nerve cells to form anywhere along the sympathetic and parasympathetic nervous systems. There are two types: chromaffin paragangliomas and nonchromaffin paragangliomas.
These two types of tumors can be benign in that the one tumor is surgically removed and does not spread or come back. However, some pheochromocytomas and paraganglioma can be metastatic.
Recent research, according to the Pheopara Alliance, shows that approximately one in 3,000 individuals have pheochromocytomas and/or paraganglioma.
“(These tumors) are extremely rare,” Dr. Daniel Pryma, division chief of Nuclear Medicine and Clinical Molecular Imaging at Penn Medicine, said in an interview with CURE®. “There are ones that are metastatic and ones that are non-metastatic, and it can be a difficult distinction. It's not like other cancers where you can tell on a biopsy which one is malignant, and which one is not. These are sort of, until they spread, in limbo.”
Symptoms of the tumor types include:
“The most famous example (of these symptoms) is Dwight Eisenhower who suffered from high blood pressure and headaches for much of his career,” Pryma said. “When he died, he was found to have a pheochromocytoma that they never knew about.”
To diagnose, a 24-hour urine test can measure the amounts of catecholamines (adrenaline or noradrenaline) or metanephrines in the urine, where an unusual amount of a substance can be a sign of disease in the organ or tissue that makes it. In addition, blood catecholamine studies can measure the amount of certain catecholamines into the blood. Moreover, CT scans, gallium dotatate scans (a procedure to detect areas of the body where cells are dividing rapidly), an MIBG scan (a procedure used to find neuroendocrine tumor), an MRI, PET scans, a plasma-free metanephrines test (a blood test that measures the amount of metanephrines in the blood) and a somatostatin receptor scintigraphy (a type of radionuclide scan that may be used to find tumors) can be used.
“The tumors have a really, really well-developed blood supply and so they tend to bleed and also if you do anything to manipulate them, you can cause a huge release of hormones, which can be fatal,” Pryma explained. “So typically, biopsies are either not done or done with significant associated pre-medication and anesthesia. So very often these go straight to surgery.”
Individuals can see an endocrinologist, a doctor who has special training in diagnosing and treating disorders of the endocrine system.
Of note, 30%-40% of those with pheochromocytomas and/or paraganglioma cases are hereditary. “There is a 50% chance you can pass it down to your children if you carry a genetic mutation,” the alliance noted in its website. “If you are diagnosed with (pheochromocytomas and/or paraganglioma), discuss genetic testing with your doctor.”
Currently, the only treatment for these tumor types is surgical resection. However, there are a few treatment options available to patients that cannot be operated on, or have tumor metastasis, according to the alliance, “and there are more studies and research being done each year to find a cure.” Azedra (iobenguane I 131) is currently the only medication approved by the Food and Drug Administration to treat these tumors.
“It’s a cancer but it behaves differently than many other cancers,” Pryma said. “It really shouldn't be treated the same way as cancer. We sometimes see patients who are diagnosed in a place that doesn’t have expertise in it, and they sort of get this kitchen sink approach where they just try sort of generic things that work in cancers. (These therapies) really aren't effective and it ends up causing the patient more harm than good. So really getting that subspecialty information sooner rather than later is helpful.”
For more information, visit pheopara.org.