Does an endocrinologist diagnose pheochromocytoma?

From the Guidelines

Yes, endocrinologists diagnose pheochromocytoma, a rare tumor that develops in the adrenal glands and causes excessive production of catecholamines, leading to symptoms like high blood pressure, headaches, sweating, and heart palpitations. Endocrinologists are medical specialists who focus on hormone-related disorders, making them particularly qualified to diagnose this condition. The diagnostic process typically involves biochemical testing of blood or urine to measure catecholamine levels or their metabolites (metanephrines), followed by imaging studies such as CT scans, MRI, or specialized nuclear medicine scans like MIBG to locate the tumor, as recommended by the American Heart Association 1. Genetic testing may also be recommended, as approximately 40% of pheochromocytomas have a hereditary component. While endocrinologists lead the diagnosis, they often work with a multidisciplinary team including radiologists, surgeons, and sometimes genetic counselors to provide comprehensive care for patients with this potentially dangerous but treatable condition. Some key points to consider in the diagnosis of pheochromocytoma include:

• The screening test of choice for pheochromocytoma/paraganglioma is measurement of circulating catecholamine metabolites, such as plasma free or urinary fractionated metanephrines 1.
• Imaging should be pursued only after biochemical evidence for a pheochromocytoma has been obtained, with computed tomography being the recommended initial imaging modality 1.
• The recent European Society of Cardiology guideline recommends suspecting pheochromocytoma in patients with signs and symptoms of catecholamine excess, a family history of pheochromocytoma, or carriers of a germline mutation in one of the pheochromocytoma-causing genes 1.
• A low threshold for a multidisciplinary review by endocrinologists, surgeons, and radiologists is recommended when the imaging is not consistent with a benign lesion, there is evidence of hormone hypersecretion, the tumor has grown significantly during follow-up imaging, or adrenal surgery is being considered 1.
• Patients with adrenal incidentalomas that display >10 HU on non-contrast CT or who have signs/symptoms of catecholamine excess should be screened for pheochromocytoma with plasma or 24-hour urinary metanephrines 1.

From the Research

Diagnosis of Pheochromocytoma

• Pheochromocytoma is a catecholamine-secreting tumor that arises from chromaffin cells of the sympathetic nervous system 2.
• The diagnosis of pheochromocytoma should first be established biochemically by measuring plasma free metanephrines and urinary fractionated metanephrines 2, 3.
• Radiological imaging tests such as computed tomography (CT) or magnetic resonance imaging (MRI) are used to localize the tumor 2, 3.
• Functional imaging tests such as scintigraphy with (123)I-metaiodobenzylguanidine (MIBG) or positron emission tomography (PET) with (18)F-F-fluorodopamine (F-DA) may also be used 2, 3.

Role of Endocrinologist

• An endocrinologist plays a crucial role in the diagnosis and management of pheochromocytoma 4, 5.
• They are responsible for interpreting biochemical test results, such as plasma and urinary metanephrines, and ordering imaging tests to localize the tumor 2, 3.
• Endocrinologists also work with other healthcare professionals, such as surgeons and radiologists, to develop a treatment plan for patients with pheochromocytoma 2, 3.

Diagnostic Criteria

• Elevated plasma free metanephrines and urinary fractionated metanephrines are key diagnostic criteria for pheochromocytoma 2, 3, 5.
• A clonidine test may be performed if the results are equivocal 5.
• Urinary free metanephrines have been shown to be a reliable method for diagnosing pheochromocytoma, with high sensitivity and specificity 6.