Extraadrenal Pheochromocytoma and Vagal Paraganglioma

Abstract

Pheochromocytomas and catecholamine-secreting paragangliomas, also referred to as extraadrenal pheochromocytomas, are rare neuroendocrine tumors that arise from chromaffin cells of the adrenal medulla and sympathetic ganglia. These tumors are uncommon causes of hypertension, accounting for <0.2% of cases (1, 2). While pheochromocytomas are inherently catecholamine-secreting tumors, paragangliomas are less likely to be functional, especially when located in the head and neck. Paragangliomas are rare and widespread tumors, commonly found in the head and neck region. The most common location for head and neck tumors is at the carotid bifurcation, while abdominal tumors are most commonly found in the periaortic-pericaval region (3). While most cases are sporadic, about one fourth of patients with pheochromocytomas are found to have genetic mutations associated with familial disorders, including multiple endocrine neoplasia type 2 syndrome associated with the RET protooncogene, von Hippel-Lindau syndrome associated with the VHL tumor suppressor gene, and mutations in succinate dehydrogenase subunits B and D. These patients typically present at a younger age and are more likely to have bilateral adrenal pheochromocytomas or paragangliomas (4). Paragangliomas are also associated with inherited syndromes caused by genetic mutations in succinate dehydrogenase subunits. Succinate dehydrogenase inactivation has been implicated with the activation of hypoxia-inducible genes involved with tumorigenesis and is an active area of cancer research (5). Rates of malignancy for pheochromocytomas have been reported as 5% to 26%, while reports of malignant paragangliomas are more rare (6, 7). Malignant tumors lack histological and molecular markers that can reliably distinguish them from benign tumors (8). In addition, malignant tumors classified as benign may present at a later time with widely metastatic disease and associated decreased overall survival (9). We present the case of a 51-year-old man with an extraadrenal pheochromocytoma and vagal paraganglioma diagnosed within several months of each other. The patient was successfully treated with surgical excision. While pheochromocytomas and paragangliomas are well documented, to our knowledge there are few if any case reports of an extraadrenal pheochromocytoma and a vagal paraganglioma in the same patient. Therefore, this case report should inform the practitioner of the possibility of multiple primary tumors when treating patients with either condition.