Extra-adrenal pheochromocytoma: Diagnosis and management

Extra-adrenal pheochromocytomas (EAPs) may arise in any portion of the paraganglion system, though they most commonly occur below the diaphragm, frequently in the organ of Zuckerkandl. EAPs probably represent at least 15% of adult and 30% of childhood pheochromocytomas, as opposed to the traditional teaching that 10% of all pheochromocytomas are at extra-adrenal sites. They may be malignant in up to 40% of the cases, though conflicting data add to the uncertainty of this point. Patients with EAPs may present with headache, palpitations, sweating, or hypertension. A small percent of patients may also be asymptomatic at presentation due to nonfunctional tumors. The diagnosis is confirmed by demonstrating elevated blood and urine levels of catecholamines and their metabolites. Imaging studies to evaluate for EAPs include CT, MRI, and ¹³¹I-labelled metaiodobenzylguanidine scintigraphy. Preoperative pharmacologic preparation, attentive intraoperative monitoring, and aggressive surgical therapy have important roles in achieving successful outcomes. Recent reports suggest that a laparoscopic approach, along with intraoperative ultrasound, can safely remove these tumors. EAPs recur and metastasize more often than their adrenal counterparts, making lifelong follow-up essential.