Malignant pheochromocytoma (paraganglioma) of the organ of Zuckerkandl: a study of two cases.

Ten percent of pheochromocytomas are found in extra-adrenal locations and are called paragangliomas. In recent years we have had the opportunity to study two patients with malignant paragangliomas of the organ of Zuckerlandl. Only 13 cases of such neoplasms have been reported previously. Our cases are of interest because of their features of recurrence, distant metastases, response to adjuvant therapy, and long survival.