An unusual case of paraganglioma of posterior mediastinum occurred in a young adult with local recurrence and multiple distant metastasis. Because of its rarity, the determinants of prognosis factor between benign and malignant paraganglioma are uncertain. In this case, we investigated abnormalities of the p53 gene and ras gene mutations in tissues of primary and metastatic lesions. Neither abnormalities of p53 gene nor ras gene mutations were detected. The molecular approach is recommended as a means of clarifying the trend towards the malignancy of paraganglioma.