Catecholamine-secreting tumors that arise from chromaffin cells of the adrenal medulla and the sympathetic ganglia are referred to as "pheochromocytomas" and "catecholamine-secreting paragangliomas" ("extra-adrenal pheochromocytomas"), respectively. Because the tumors have similar clinical presentations and are treated with similar approaches, many clinicians use the term "pheochromocytoma" to refer to both adrenal pheochromocytomas and catecholamine-secreting paragangliomas. However, the distinction between pheochromocytoma and paraganglioma is an important one because of implications for associated neoplasms, risk for malignancy, and genetic testing.
The clinical presentation of and approach to diagnosis of pheochromocytoma are reviewed here. The genetics and treatment of pheochromocytoma, and the clinical manifestations, diagnosis, and treatment of paragangliomas are discussed separately. (See "Pheochromocytoma in genetic disorders" and "Treatment of pheochromocytoma in adults" and "Paragangliomas: Epidemiology, clinical presentation, diagnosis, and histology".)
Catecholamine-secreting tumors are rare neoplasms, probably occurring in less than 0.2 percent of patients with hypertension [1,2]. It is estimated that the annual incidence of pheochromocytoma is approximately 0.8 per 100,000 person years . However, this is likely to be an underestimate as 50 percent of pheochromocytomas were diagnosed at autopsy in one series . Although pheochromocytomas may occur at any age, they are most common in the fourth to fifth decade and are equally common in men and women . Tumor characteristics are described below. (See 'Tumor characteristics' below.)
Pheochromocytoma is usually suggested by the history in a symptomatic patient, discovery of an incidental adrenal mass, or the family history in a patient with familial disease. In one report of 107 patients, the average age at diagnosis was 47 years, and the average tumor size was 4.9 cm .
Classic triad — The classic triad of symptoms in patients with a pheochromocytoma consists of episodic headache, sweating, and tachycardia [1,6]. About half have paroxysmal hypertension; most of the rest have what appears to be primary hypertension (formerly called "essential" hypertension) or normal blood pressure. Most patients with pheochromocytoma do not have the three classic symptoms [7,8], and patients with primary hypertension may have paroxysmal symptoms .