Dr. Miller treated us to an interesting noon report where a young man presented with seizure activity: he was ultimately found to have a paraganglioma.
What is a paraganglioma?
Paragangliomas are neuroendocrine tumors that arise from the extra-adrenal autonomic paraganglia. They consist of neuroendocrine cells that are derived from para or sympathetic ganglia and can be both functional and non-functional .
These are rare: there are approximately 500 to 1600 cases in the US per year (0.8 per 100,000). Most are diagnosed in 3rd-5th decade of life. Most paragangliomas are benign, but up to 20% are malignant.
How do paragangliomas present?
The presentation of paragangliomas can vary. They can just be an incidental finding in an asymptomatic patient or they can present secondary to mass effect. They can also present with symptoms from catecholamine release, including hypertensive crises. The classic triad is headache, sweating, and palpitations. Catecholamine release can be triggered by a variety of things, including anxiety, exercise, or anything that increases intra-abdominal pressure.
Be aware that if your tumor is one that secretes dopamine, patients will NOT be hypertensive. They will be normotensive to hypotensive.
Fun fact: "Micturition syncope" is the clinical hallmark of a catecholamine-secreting bladder paraganglioma.
This catecholamine release sounds just like a pheochromocytoma...
A pheo is a paraganglioma in the adrenal gland! Paragangliomas are outside of the adrenal gland anywhere along the sympathetic chain.
Additionally, pheochromocytomas produce Epinephrine > Norepinephrine. Paragangliomas do not produce epinphrine. They almost exclusively norepinprhine, but they can also secrete dopamine.
How do I workup a patient with a suspected paraganglioma?
Get plasma and urine catecholamines and metanephrines. Additional imaging should be ordered as well:
An MIBG scan is used for localization of known or suspected neuroectodermally derived tumors, including pheochromocytoma, ganglioneuroma, ganglioneuroblastoma, paraganglioma, carcinoid tumor and neuroblastoma. It combines a small amount of radioactive material with a substance called metaiodobenzylguanidine (MIBG) to find these neuroectoderm tumors.
A Dotatate PET scan is also used to evaluate neuroendocrine tumors. A small amount of a radioactive drug called Dotatate is given by injection before the PET scan.
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