Pheochromocytomas and related Paragangliomas
Catecholamine-producing tumors may arise in the adrenal medulla (pheochromocytomas) or in extraadrenal chromaffin cells (paragangliomas). Their prevalence is about 0.1% in patients with hypertension and 4% in patients with a fortuitously discovered adrenal mass.
These tumors may be sporadic or part of any of several genetic diseases: familial pheochromocytoma-paraganglioma syndromes, multiple endocrine neoplasia type 2, neurofibromatosis 1 and von Hippel-Lindau disease.
Familial cases are diagnosed earlier and are more frequently bilateral and recurring than sporadic cases. The most specific and sensitive diagnostic test for the tumor is the determination of plasma or urinary metanephrines. The tumor can be located by computed tomography, magnetic resonance imaging and metaiodobenzylguanidine scintigraphy. Treatment is resection of the tumor, generally by laparoscopic surgery.
About 10% of tumors are malignant either at first operation or during follow-up, malignancy being diagnosed by the presence of lymph node, visceral or bone metastases. Recurrences and malignancy are more frequent in cases with large or extraadrenal tumors. Treatment for malignant recurrence includes surgery, therapeutic embolization, chemotherapy and metabolic radiotherapy. Patients, especially those with familial or extraadrenal tumors, should be followed-up indefinitely.