Purpose: Pheochromocytoma (PCC) and paraganglioma (PG) are evaluated and treated similarly. This study evaluates the hypothesis that tumor characteristics and outcome of patients with PCC and PG are equivalent.
Methods: Records of patients from a single institution undergoing resection of PCC or PG from 1999 to 2010 were reviewed. Data were collected for demographics, operative records, laboratory and pathologic results, adjuvant and palliative therapy given, recurrence, and length of survival. Descriptive statistics were used to describe differences between patients with benign and malignant PCC and PG. Analysis was performed using the Wilcoxon-Mann-Whitney test with p = 0.05 considered as significant.
Results: One hundred fifteen patients were identified (106 PCC and nine PG). Of the tumors, 5.2% were bilateral and 10.4% were malignant. Forty-three of the 115 patients underwent genetic testing; 21 out of 37 (56.8%) PCC and five out of six (83.3%) PG had a genetic mutation. Twelve patients (seven PCC and five PG) had malignant tumors. Malignant PG (mPG) exhibited more invasive pathologic characteristics. The median sizes of benign and malignant PCC (mPCC) were 4.0 (0.7-14 cm) and 5.5 cm (3.7-11.2 cm), respectively, p = 0.03. The median sizes of benign and mPG were 4.1 (2.7-5.4 cm) and 5.8 cm (4-6.2 cm), respectively, p = 0.11. Sites of recurrence were similar between the groups. Patients with mPG received chemotherapy more often than those with mPCC. With a median follow-up of 54.7 months (2.0-185.3), two out of five mPG and zero out of seven mPCC had died of the disease.
Conclusion: Tumor size does not appear to correlate with malignancy in a clinically significant manner. Malignant paraganglioma may be more aggressive than malignant pheochromocytoma and is frequently offered more adjuvant therapy. PCC and PG should be evaluated separately in future analyses of these diseases.