Pheochromocytoma: Causes, Symptoms, Diagnosis and Treatment — Overview, Diagnosis & Treatment Options | MyMedicPlus

Pheochromocytoma is a catecholamine-secreting neuroendocrine tumor arising from adrenal medullary chromaffin cells. Rare, with approximately 2-8 cases per million annually. Approximately 10-15% are malignant (defined by metastases). Often called the '10% tumor' due to historic associations with bilaterality, malignancy, and hereditary origin.

Approximately 40% are hereditary: VHL syndrome, MEN2A/2B (RET mutations), NF1, and SDH subunit gene mutations (SDHB most common in malignant disease). SDHB mutation carriers have the highest risk of malignant behavior. Many cases are diagnosed incidentally on imaging performed for other indications.

Classic triad: episodic headache, sweating, and palpitations. Paroxysmal or sustained hypertension (resistant to standard antihypertensives). Anxiety, pallor, weight loss, and hyperglycemia. Symptoms can be triggered by tumor palpation, anesthesia induction, certain medications (metoclopramide, tricyclic antidepressants, glucagon), or physical activity.

Biochemical: plasma free metanephrines or 24-hour urine fractionated metanephrines (sensitivity >96%, gold standard). CT or MRI for anatomic localization. 123I-MIBG scintigraphy or 68Ga-DOTATATE PET/CT for multifocal or metastatic disease. Germline genetic testing (SDH panel, VHL, RET, NF1) recommended for all patients.

Preoperative alpha-adrenergic blockade with phenoxybenzamine for 10-14 days is mandatory before surgical resection to prevent intraoperative hypertensive crisis. Laparoscopic adrenalectomy is standard for most tumors. Beta-blockade only after adequate alpha-blockade to prevent reflex tachycardia. 131I-MIBG or PRRT for metastatic MIBG/SSTR-avid disease. Sunitinib or cabozantinib for refractory metastatic disease.

Benign adrenalectomy achieves cure in over 95% of patients with regular long-term monitoring. Malignant (metastatic) pheochromocytoma: 5-year survival approximately 36-60%, varying with SDHB mutation status and disease extent. Lifelong surveillance with annual biochemical testing is essential due to late recurrence risk.