Pheochromocytomas are rare catecholamine-secreting neuroendocrine tumors derived from chromaffin tissue of the adrenal medulla. Such tumors arising from the sympathetic ganglia of the thorax, abdomen, or pelvis are termed “paragangliomas” or “extra-adrenal pheochromocytomas.” The classic symptoms of these tumors are due to excess circulating levels of norepinephrine, epinephrine, or dopamine. Although 21% may be asymptomatic, the most common symptoms associated with pheochromocytomas include sweating, palpitations, and headaches in association with intermittent hypertension. If left untreated, excess catecholamines may result in hypertensive crisis leading to cardiac complications, cerebrovascular stroke, or ultimately sudden death. These catecholamine-secreting tumors are most commonly sporadic, but about 30% of patients have this disease as part of a familial disorder such as multiple endocrine neoplasia type 2 (MEN2) or von Hippel-Lindau (VHL) syndrome. Although most are benign, accurate recognition of pheochromocytomas with malignant potential and distant metastases remains a major diagnostic challenge. Advances in the field of molecular genetics have led to novel diagnostic and therapeutic strategies in an attempt to address this dilemma. Surgical excision of pheochromocytomas and paragangliomas is the mainstay of treatment and offers the only potential for cure. This chapter focuses on recent developments in the diagnosis of pheochromocytomas, encompassing biochemical, radiologic, histologic, and molecular analyzes. In addition, novel therapeutic strategies and advances in individualized targeted therapies for malignant pheochromocytomas will be discussed.
Part of the book: Clinical Management of Adrenal Tumors