A paraganglioma is a rare neuroendocrine neoplasm that may develop at various body sites (including the head, neck, thorax and abdomen). When the same type of tumor is found in the adrenal gland, they are referred to as a pheochromocytoma. They are rare tumors, with an overall estimated incidence of 1 in 300,000.[1] There is no test that determines benign from malignant tumors; long-term follow-up is therefore recommended for all individuals with paraganglioma.[2]

Reference
Wiki: Hereditary paraganglioma