Pheochromocytoma.
Pheochromocytoma is a rare tumor, but it represents a potentially curable form of hypertension. In patients with inherited pheochromocytoma, benign and bilateral tumors are more common. The diagnosis of pheochromocytoma rests in biochemical confirmation of catecholamine excess. Plasma-free metanephrine levels are arguably the most sensitive and specific test for the biochemical diagnosis of pheochromocytoma in high-risk patient populations. A timed 24-hour urine collection for total catecholamines and metabolic products (eg, vanillylmandelic acid and metanephrines) is the favored confirmatory test. Localization is most commonly accomplished with high-resolution computed tomography imaging, but magnetic resonance imaging can also be used. If both of these imaging modalities are nonlocalizing or equivocal, then radiolabeled meta-iodobenzylguanidine or somatostatin can be used to identify an adrenal or extra-adrenal tumor (paraganglioma). These imaging modalities can be used in the evaluation of patients with suspected or confirmed recurrent or metastatic disease. Systemic therapies for the treatment of patients with recurrent or metastatic disease have been disappointing. Radiation therapy is best applied for palliative relief of pain associated with bony metastases. In the absence of radiographic evidence for local tumor invasion, laparoscopic resection of small- to medium-sized (< 6 cm) pheochromocytomas is indicated. Abundant evidence indicates that this approach is safe and well tolerated and results in more rapid recovery and less long-term wound morbidity compared to open anterior or posterior adrenalectomy. Open anterior adrenalectomy is appropriate for patients with large or recurrent tumors, suspected or documented locoregional invasion, or for those patients in whom a laparoscopic approach is technically contraindicated. For selected patients with pheochromocytoma in the von Hipple-Lindau syndrome or multiple endocrine neoplasia type 2 setting in which the cumulative incidence of clinical bilateral tumors is high, a cortical-sparing approach may minimize the risk of Addisonian complications.