Pheochromocytoma

Pheochromocytoma is a rare neuroendocrine tumor arising from chromaffin cells of the adrenal medulla. Tumors located outside the adrenal gland along the sympathetic chain are called paragangliomas. Most pheochromocytomas secrete catecholamines (epinephrine, norepinephrine, and dopamine), producing episodic or sustained hypertension and a classic symptom triad of headaches, sweating, and tachycardia, often with anxiety, tremor, and palpitations. Attacks can be triggered by stress, exertion, medications, or surgery and may lead to cardiovascular complications if untreated.

Diagnosis relies on biochemical evidence of catecholamine excess. Preferred tests measure plasma free metanephrines or 24-hour urine fractionated metanephrines and catecholamines, with high sensitivity. Positive results warrant tumor localization with imaging, typically contrast-enhanced CT or MRI. Functional imaging (such as MIBG scintigraphy or PET/CT with 68Ga-DOTATATE, 18F-FDOPA, or 18F-FDG) is used when initial imaging is inconclusive or for staging. Given a substantial hereditary component, genetic testing is recommended for all patients, with associations including RET (MEN2), VHL, NF1, and SDHx mutations.

Treatment centers on safe tumor removal. Preoperative management uses alpha-adrenergic blockade (e.g., phenoxybenzamine or doxazosin) with volume optimization, followed by beta-blockade if needed. The definitive therapy is surgical resection; cortical-sparing adrenalectomy may be considered in bilateral disease. Metastatic or unresectable disease may require additional therapies.

Prognosis is favorable after complete resection but depends on stage and genotype; SDHB mutations carry higher malignancy risk. Lifelong follow-up with periodic biochemical testing and imaging is recommended to monitor for recurrence or new tumors.