Pheochromocytoma: Causes, Symptoms, and Diagnosis

“Medicine is a science of uncertainty and an art of probability."

— William Osler

Introduction

In medicine, the most dangerous conditions are often the ones that go unnoticed. Pheochromocytoma is a rare tumor that forms in the adrenal glands and secretes excess stress hormones—usually catecholamines like adrenaline and noradrenaline. While it may be uncommon, the consequences of missing a diagnosis can be severe, including dangerously high blood pressure, cardiovascular complications, and sudden life-threatening events.

Because its symptoms often mimic more common conditions like anxiety, panic attacks, or essential hypertension, pheochromocytoma is frequently overlooked in routine evaluations. Yet for those affected, timely recognition and appropriate testing can be lifesaving.

This article will explain what pheochromocytoma is, how it develops, the symptoms to watch for, and how it’s diagnosed—helping bring clarity to a condition that often hides in plain sight.

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Could anxiety symptoms or sudden blood pressure spikes be something more serious? In this episode, we dive into pheochromocytoma, a rare adrenal tumor that can mimic stress and panic but carries serious health risks if left undiagnosed.

Tap play below to learn the warning signs, how it’s diagnosed, and why early detection is key to a full recovery.

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What Is Pheochromocytoma?

Pheochromocytoma is a rare neuroendocrine tumor that originates from chromaffin cells in the adrenal medulla—the inner part of the adrenal glands located above each kidney. These tumors are usually benign but can sometimes be malignant. What makes pheochromocytomas clinically significant is their ability to secrete excessive amounts of catecholamines, such as adrenaline (epinephrine), noradrenaline (norepinephrine), and dopamine.(Cleveland Clinic)

Catecholamines are the same hormones released during the body’s "fight or flight" response. When released inappropriately or continuously due to a tumor, they can cause a wide range of symptoms and complications, most notably severe or episodic hypertension. In many cases, this excess hormone secretion goes unrecognized for months or even years, especially if symptoms occur in short, intermittent bursts.

Although pheochromocytomas are rare—with an estimated incidence of 2 to 8 cases per million people annually—they are an important diagnostic consideration in individuals with resistant or unexplained high blood pressure, particularly when accompanied by symptoms like headaches, palpitations, or sweating.

According to the National Cancer Institute, timely diagnosis and treatment of pheochromocytoma are essential because unrecognized catecholamine excess can lead to life-threatening cardiac events, stroke, or end organ damage.

Causes and Risk Factors

The exact cause of pheochromocytoma is not always known, but a significant number of cases—particularly in younger patients—are linked to genetic mutations and inherited syndromes. Up to 30% of individuals with pheochromocytoma carry a hereditary genetic mutation, which means they may have a family history of similar tumors or related conditions.

Pheochromocytoma can occur on its own or as part of a larger genetic syndrome, including:

• Multiple Endocrine Neoplasia type 2 (MEN2) – A syndrome that also involves medullary thyroid cancer and hyperparathyroidism.

• Von Hippel-Lindau disease (VHL) – A genetic condition that can cause tumors and cysts in multiple organs.

• Neurofibromatosis type 1 (NF1) – A disorder that affects nerve tissue growth and increases tumor risk.

• Familial paraganglioma syndromes – These involve tumors that arise from extra-adrenal chromaffin tissue, known as paragangliomas.

Other risk factors may include having a close relative with one of these conditions, or previously diagnosed adrenal tumors or paragangliomas. Pheochromocytomas most often appear in adults between the ages of 30 and 50 but can occur at any age. The Mayo Clinic emphasizes the importance of genetic testing in patients diagnosed with pheochromocytoma—especially those under 45 or those with bilateral or recurring tumors. 

Early identification of a hereditary cause is not only essential for treatment but also helps guide screening in close family members who may be at risk.

Symptoms and Clinical Presentation

Pheochromocytoma is often called “the great mimic” because its symptoms overlap with a wide range of more common conditions, including anxiety disorders, panic attacks, and essential hypertension. What makes it distinct is the way symptoms often occur in episodes—sudden, intense, and unpredictable bursts of physiological activity caused by surges in catecholamine hormones.

The classic triad of symptoms includes:

• Headache

• Sweating (often profuse and unrelated to external temperature)

• Palpitations or a rapid heartbeat

These episodes may last from minutes to hours and are often accompanied by elevated blood pressure. In some cases, blood pressure may spike dramatically, posing immediate cardiovascular risks. Additional symptoms can include:

• Tremors or shaking

• Anxiety or a sense of impending doom

• Pale or flushed skin

• Chest pain

• Shortness of breath

• Nausea or abdominal pain

Some individuals may also experience chronic high blood pressure between episodes, especially if the tumor has been active for a prolonged period. According to the Endocrine Society, the presence of high blood pressure in combination with these paroxysmal symptoms should raise suspicion for pheochromocytoma—particularly when conventional antihypertensive treatments fail to provide full control.

It’s also worth noting that physical exertion, surgery, anesthesia, or certain medications can trigger symptomatic episodes in people with undiagnosed tumors, making early recognition crucial to prevent dangerous complications.

How Pheochromocytoma Is Diagnosed

Diagnosing pheochromocytoma requires a combination of clinical suspicion, biochemical testing, and imaging (nichd). Because the condition is rare and symptoms can mimic more common disorders, diagnosis is often delayed—especially when symptoms are intermittent or mild. However, early testing is essential to avoid potentially life-threatening complications.

The first step in diagnosis typically involves biochemical confirmation. This means measuring the levels of catecholamines and their metabolites in the blood or urine. The most widely used tests include:

• Plasma free metanephrines – This blood test measures stable byproducts of catecholamines and is highly sensitive for detecting pheochromocytoma.

• 24-hour urine collection – Measures catecholamines and metanephrines over a full day, providing a comprehensive view of hormone secretion.

If elevated levels are found, imaging is used to localize the tumor. Common anatomical imaging modalities include:

• CT scan (computed tomography) of the abdomen and pelvis

• MRI (magnetic resonance imaging), which is especially helpful in younger patients or those with known genetic syndromes

For functional imaging, several nuclear medicine options are available, each with unique strengths and limitations depending on the tumor’s behavior, genetic background, and clinical context.

• MIBG PET (metaiodobenzylguanidine positron emission tomography) – This imaging modality is highly specific for detecting catecholamine-secreting tumors, including most pheochromocytomas. It uses a norepinephrine analog to target adrenergic tissue and is especially valuable in localizing adrenal tumors during initial diagnosis and surgical planning. However, its sensitivity decreases in metastatic cases and in paragangliomas, particularly those associated with SDHB mutations.

• Ga-68 DOTATATE PET/CT – offers higher sensitivity than MIBG, especially for detecting extra-adrenal paragangliomas and metastatic spread. It binds to somatostatin receptors, which are often overexpressed in neuroendocrine tumors, but it is less specific for pheochromocytomas compared to MIBG.

• 18F-FDG PET – is typically reserved for aggressive or poorly differentiated tumors and for patients with known genetic mutations that may lead to metastatic disease. Its strength lies in identifying tumors with high metabolic activity that may be missed by MIBG or somatostatin receptor imaging.

Selecting the most appropriate imaging modality depends on clinical suspicion, genetic background, and prior imaging results. As noted by the European Association of Nuclear Medicine, a tailored approach using both anatomical and functional imaging ensures the highest diagnostic yield in pheochromocytoma and paraganglioma evaluation.

Treatment Options

The primary treatment for pheochromocytoma is surgical removal of the tumor, most often through a procedure called adrenalectomy. In most cases, this surgery is curative—especially when the tumor is confined to the adrenal gland and has not metastasized. However, because of the potential for dangerous surges in catecholamines during surgery, proper preoperative preparation is absolutely essential.

Prior to surgery, patients are typically started on alpha-adrenergic blockers (such as phenoxybenzamine or doxazosin) to stabilize blood pressure and reduce the risk of intraoperative hypertensive crises. In some cases, beta-blockers may be added after adequate alpha-blockade to control tachycardia, but they should never be used alone, as unopposed alpha stimulation can worsen blood pressure and vascular resistance.(Current Medical Diagnosis & Treatment)

For patients with bilateral tumors, genetic syndromes, or metastatic disease, the treatment approach may vary. Options may include:

• Cortical-sparing adrenalectomy to preserve adrenal function

• MIBG radiotherapy for unresectable or MIBG-avid metastatic disease

• Peptide receptor radionuclide therapy (PRRT) using radiolabeled somatostatin analogs for DOTATATE-positive tumors

• Chemotherapy (e.g., cyclophosphamide, vincristine, and dacarbazine) in aggressive or refractory cases

• Targeted therapies in clinical trial settings for patients with known mutations (such as SDHB)

Long-term follow-up is essential, even after successful surgery. Recurrence can occur, particularly in hereditary cases or when complete resection isn't possible. The Endocrine Society Clinical Practice Guidelines recommend lifelong monitoring with periodic biochemical testing and imaging in high-risk individuals.

Prognosis and Long-Term Outlook

With timely diagnosis and proper treatment, the prognosis for patients with pheochromocytoma is generally favorable. For those with localized, benign tumors that are fully resected, long-term outcomes are excellent, and symptoms often resolve shortly after surgery. Most patients experience normalization of blood pressure, improved cardiovascular stability, and relief from episodic symptoms like palpitations and anxiety.

However, the long-term outlook can be more complex in certain situations. Individuals with hereditary forms of pheochromocytoma, bilateral tumors, or extra-adrenal paragangliomas face a higher risk of recurrence or metastasis. In these cases, close follow-up is essential to detect recurrence early and manage any long-term complications. Recurrences can occur many years after initial treatment, particularly in patients with SDHB gene mutations, which are associated with a higher risk of malignancy.

Lifelong surveillance typically includes:

• Periodic measurement of plasma or urine metanephrines

• Routine imaging (especially in those with known genetic risk)

• Clinical assessment for return of symptoms

According to the American Association of Clinical Endocrinologists, multidisciplinary management and genetic counseling are recommended for patients with familial or metastatic pheochromocytoma. Early intervention not only improves prognosis but also helps reduce the risk of serious cardiovascular events associated with undiagnosed or recurrent catecholamine excess.

Conclusion

Pheochromocytoma may be rare, but its impact can be profound—especially when left undiagnosed. Its ability to mimic more common conditions like anxiety or essential hypertension often leads to delayed recognition, placing patients at risk for life-threatening cardiovascular events. Yet with greater clinical awareness, modern diagnostic tools, and effective surgical treatment, outcomes for most patients can be excellent.

Understanding the signs, recognizing the risk factors, and pursuing appropriate testing can make all the difference. Whether you're a patient experiencing unexplained symptoms or a healthcare provider facing a diagnostic challenge, keeping pheochromocytoma on the differential can be life-saving.

For more expert insights into complex conditions and accessible testing options, visit Quick Lab Mobile or explore more educational content through The Lab Report.

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