Pheochromocytoma and paraganglioma are rare tumors that form from neuroendocrine cells. Neuroendocrine cells release hormones into the blood when they receive a signal from the nervous system. Neuroendocrine cells are found all through the body.

Paragangliomas usually form near the carotid artery and along nerve pathways in the head, neck, and spine. Pheochromocytomas form in the adrenal medulla (the center of the adrenal gland found on top of each kidney).

Pheochromocytomas and some paragangliomas release the hormones adrenaline and noradrenaline into the blood. This may cause symptoms such as high blood pressure, pounding headaches, flushing, and heart palpitations.

Certain inherited disorders increase the risk of pheochromocytoma or paraganglioma. These include multiple endocrine neoplasia 2 syndrome, types A and B , von Hippel-Lindau syndrome, and neurofibromatosis type 1.

Pheochromocytomas and paragangliomas may be benign or malignant.