Predictive Characteristics of Malignant Pheochromocytoma

ABSTRACT

PURPOSE: The prognosis of patients with malignant pheochromocytoma is poor, but the predictive factors are not well understood. We aimed to identify the clinical characteristics predictive of malignancy after initial surgical removal in patients with pheochromocytoma. MATERIALS AND METHODS: We retrospectively reviewed the records of 152 patients diagnosed with pheochromocytoma, including 5 (3.3%) with metastasis at the time of the initial surgical excision and 12 (7.9%) who developed metastasis during follow-up. To determine the factors predictive of malignancy, we compared clinical, radiographical, and urinary chemical findings between patients with benign and malignant disease. Mean follow-up was 41.5 months (range, 0.9-298 months) after surgery. RESULTS: Malignant tumors were significantly larger than benign tumors (11.1+/-4.0 cm vs. 6.2+/-3.4 cm, p5.5 cm; 90.6% vs. 81.2%, p=0.025) and higher 24-hour secretion of vanillylmandelic acid (>2.1 vs. 5.5 cm) and minimally elevated 24-hour urinary vanillylmandelic acid (< or =2.1 mg/day/cm) were significantly associated with a higher probability of a malignant pheochromocytoma portending a lower metastasis-free survival and mandating more rigorous follow-up after surgery.