Pheochromocytoma

00:00 Welcome back. Thanks for joining me on this discussion of pheochromocytoma in the section of general surgery.

00:07 Pheochromocytoma used to be one of my favorite topics as a medical student because the word is kind of fun to say.

00:14 I challenge you to say it ten times fast. Now, let’s get started.

00:18 Pheochromocytomas are catecholamine secreting tumors specifically located the vast majority of the time in the adrenal medulla.

00:27 Remember, the adrenal gland has multiple layers.

00:30 In the inner core called the adrenal medulla, norepinephrine and epinephrine are secreted.

00:36 Also important to remember, 10% of pheochromocytomas are actually outside of the adrenal gland.

00:44 The rule of 10 is important to mention with pheochromocytomas, as 10% are malignant and 10% are familial.

00:52 These are commonly called paragangliomas or organ of Zuckerkandl.

01:01 In this image marked in red is the organ of Zuckerkandl or a paraganglioma commonly found at the aortic bifurcation.

01:11 They contain neural crest tissue usually at the level of the aortic bifurcation or at the inferior mesenteric artery takeoff.

01:19 What are some of the common symptoms of pheochromocytoma? Here, you see the gentleman with episodic headaches. They can be quite severe. Diaphoresis, also catecholamine-induced; and very importantly, tachycardia. Now, the combination of episodic headaches, diaphoresis, and tachycardia is a classic association and incredibly high-yield.

01:46 I recommend that you keep that in mind. However, clinically, this triad is actually a rare finding.

01:53 Remember very importantly, pheochromocytomas can result in potentially fatal cardiac arrhythmias.

02:00 Therefore, you must have a high index of suspicion in patients with difficult to treat hypertension.

02:06 Speaking of which, most patients with pheochromocytoma result in hypertension and the reason is because of the increased catecholamine secretions.

02:19 Let’s take a look at what laboratory findings may help you diagnose a pheochromocytoma.

02:26 Unfortunately, your general chemistries and your CBCs may not be very helpful.

02:31 However, specific to the diagnosis of pheochromocytoma are urine or plasma metanephrines.

02:39 Plasma metanephrines are more sensitive but less specific and conversely, urine catecholamines and metanephrines are less sensitive but more specific.

02:50 A downfall of urine catecholamines is that it requires a 24-hour urine collection.

02:56 That can be difficult on an outpatient basis.