Sporadic pheochromocytoma/secreting paraganglioma

Sporadic pheochromocytoma/secreting paraganglioma refers to catecholamine-producing tumors that arise without an identifiable hereditary genetic cause. Pheochromocytomas originate from the chromaffin cells of the adrenal medulla, while secreting paragangliomas (also called extra-adrenal pheochromocytomas) develop from sympathetic or parasympathetic paraganglia located along the sympathetic chain in the abdomen, thorax, or head and neck region. These tumors produce excess catecholamines (epinephrine, norepinephrine, and/or dopamine), which affect the cardiovascular, endocrine, and nervous systems. Historically, approximately 60-70% of pheochromocytomas and paragangliomas were considered sporadic, though advances in genetic testing have revealed hereditary causes in an increasing proportion of cases. Key symptoms result from catecholamine excess and classically include episodic or sustained hypertension, headaches, profuse sweating, palpitations, and anxiety or a sense of impending doom. Patients may also experience pallor, tremor, nausea, weight loss, and hyperglycemia. Hypertensive crises can be life-threatening and may be triggered by physical exertion, anesthesia, certain medications, or tumor manipulation. While the majority of these tumors are benign, approximately 10-15% may be malignant, with the potential for metastasis to lymph nodes, bone, liver, or lungs. Diagnosis involves measurement of plasma free metanephrines or 24-hour urinary fractionated metanephrines, followed by anatomical imaging (CT or MRI) and functional imaging (such as MIBG scintigraphy or 68Ga-DOTATATE PET/CT) for tumor localization. The primary treatment is surgical resection, typically laparoscopic adrenalectomy for pheochromocytomas, preceded by adequate alpha-adrenergic blockade (usually with phenoxybenzamine or doxazosin) to prevent intraoperative hypertensive crises. Beta-blockers may be added after alpha-blockade is established. For malignant or metastatic disease, treatment options include combination chemotherapy (cyclophosphamide, vincristine, and dacarbazine), 131I-MIBG therapy, targeted therapies, and peptide receptor radionuclide therapy (PRRT). Long-term follow-up is recommended due to the risk of recurrence.

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