Comparison of adrenal and extraadrenal pheochromocytomas.

Overview

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 ATs. 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.