The management of patients with pheochromocytomas and the malignant potential of benign pheochromocytomas have challenged physicians for several decades. The usual criteria used to evaluate other types of tumors (e.g., cellular atypia, increased mitotic activity, and vascular or capsular invasion) have not been considered reliable predictors of malignancy in patients with pheochromocytomas.
Goldstein and associates reviewed the presentation, localization, surgical management, pathology and long-term outcomes in patients with pheochromocytomas. During a 48-year period, 104 patients presented to the authors with 108 pheochromocytomas. Before 1968, routine provocative tests included histamine and glucagon stimulation and regi-tine infusion. Beginning in 1968, virtually all patients underwent biochemical confirmation of pheochromocytoma by increased catecholamine and catecholamine metabolite concentration in a 24-hour urine sample or elevated plasma catecholamine concentration.
Historically, several surgical approaches have been used to resect pheochromocytomas. From 1979 through 1998, a midline abdominal incision was the preferred approach. More recently, laparoscopy has been selectively used and will probably become the preferred approach in the future. The final diagnosis of malignancy was based on the finding of metastatic disease or gross tumor infiltration into surrounding structures (e.g., liver, kidney or spine). Tumors with microscopic capsular or vascular invasion were considered at risk for malignancy.
The average age at surgery was 42.3 years. Careful documentation of a past history of hypertension was noted in only 42 percent of patients, while 82 percent of patients actually presented with symptoms of hypertension. Other common symptoms of pheochromocytoma included headache, palpitations and sweating. Currently, magnetic resonance imaging is the technique of choice, with high specificity and sensitivity.
Twenty-six patients with extra-adrenal pheochromocytomas were identified. The rate of malignancy and survival rates were not statistically significant between patients with adrenal versus extra-adrenal pheochromocytomas.
The authors conclude that extra-adrenal pheochromocytomas may not have greater malignant potential than adrenal tumors. Patient survival rates were similar for both types of tumors. All patients with pheochromocytomas should be followed closely throughout their lives, with biochemical screening performed if a suspicious symptom occurs. Metastases have occurred up to 15 years after resection.