Comparison of adrenal and extraadrenal pheochromocytomas

Background. It is commonly believed that extraadrenal tumors (EAT) of the paraganglion system are more likely to be malignant than adrenal tumors (AT) and carry a poorer prognosis. We analyzed 73 paraganglion tumors (PT) to determine whether EATS are more likely to be malignant or have a poorer prognosis than A Ts. Methods. A review of patients with PTs at three institutions was performed. Malignant tumors were defined as those that metastasized. Comparison of the frequencies of malignant tumors was performed by chi-squared analysis. Survival distributions were determined by Kaplan and Meier analysis. Comparison of survival distributions was performed by log-rank analysis. Results. There were 73 patients. There were 51 ATs, of which 24 were malignant, and 22 EATS, of which 11 were malignant (p = 0.82). The 5-year survival rate was 77% for patients with ATs and 82% for patients with EATS (p = 0.29). The 5-year survival rate for patients with malignant ATs was 57%, and 74% for patients with malignant EATS (p = 0.15). There were no significant differences in disease free survival rates on the basis of tumor site. Conclusions. We were unable to demonstrate that EATS are significantly more likely to be malignant than ATs. The survival and disease free survival rates for malignant ATs and EATS are similar, and among malignant tumors, there may be no prognostic value of the anatomic location.