Pheochromocytoma and paraganglioma in Fontan patients: Common more than expected

Objective: Pheochromocytoma and paraganglioma (extra-adrenal pheochromocytoma) are rare neuroendocrine tumors that arise from the neuroendocrine cells. Chronic hypoxia is known as a possible cause, and a strong link between cyanotic congenital heart disease and these tumors has been reported. However, reports of phechromocytoma/paraganglioma in Fontan patients were scarce. We herein report seven cases of phechromocytoma/paraganglioma after Fontan operation at a single tertiary center. Methods: We retrospectively reviewed medical records and imaging studies who diagnosed as phechromocytoma/paraganglioma after Fontan operation in Seoul National University Children's Hospital. Results: Seven patients were identified during follow-up after Fontan operation, and the prevalence was 2.5% among Fontan patients greater than 10 years old on active follow-up. Three patients were diagnosed as phechromocytoma and 4 patients as paraganglioma. Median time interval between Fontan operation and diagnosis of pheochromocytoma/paraganglioma was 21.4 years (range, 10.4-29.7 years). Resting percutaneous oxygen saturation varied from 77% to 94%. All patients underwent complete tumor resection. Phechromocytoma recurred in two patients, of whom one patient died at the age of 18 years due to the tumor progression with multiple metastasis and aggravation of heart failure with profound cyanosis. Pheochromocytoma/paraganglioma developed after hepatocellular carcinoma in two patients. Conclusion: Phechromocytoma/paraganglioma could occur in Fontan patients more than expected. Because it is curable by tumor resection during its early phase, early diagnosis and treatment of pheochromocytoma are crucial in Fontan patients not to make hemodynamic deterioration and aggravation of heart failure.