Cardiac Chromaffin Cell Pheochromocytoma

The most common presentations of cardiac pheochromocytomas are catecholamine-related symptoms:[2] palpitations, sweating, diaphoresis, hypertension, tachycardia, dizziness, headache, syncope, perspiration, and flushing. Unlike other primary cardiac tumors, shortness of breath is uncommon. Although uncommon, some patients may present with chest pain. The likely explanation of the chest pain is that the tumor itself may mimic angina if it does not get enough blood supply. Sometimes initial presentation can be nonspecific: fever, fatigue, and weight loss. These tumors are rarely asymptomatic.

Once there is a suspicion of a pheochromocytoma, one should keep in mind that 98% of these tumors are intra-abdominal (90% in the adrenal medulla), and less than 2% are found in the chest. Of these in the chest, CP is one of the rarest ones.

Biochemical Testing

• Cardiac pheochromocytoma can be confirmed or excluded with biochemical testing by using serum and urine metanephrines.[8] Plasma metanephrines have sensitivity and specificity of 99% and 89%, respectively, while urine metanephrines have sensitivity and specificity of 97% and 93%, respectively. Although less accurate compared to metanephrines, urine, and total serum catecholamines can be obtained as well.
• Once pheochromocytoma is diagnosed with chemical testing, then the tumor has to be localized. Since the abdomen, especially the adrenal gland, is the most common site, intra-abdominal imagings should be done to rule out intra-abdominal pheochromocytomas.

Tumor Localization

The most difficult part of this tumor is not by diagnosing it but to localize it. There is a number of imagings (including but not limited to CT or enhanced CT, PET scan, MRI, echocardiogram, labeled metaiodobenzylguanidine (MIBG), or Tc labeled octreotide) that can be used. The most important imagings for CP localization will be reviewed below.

• Iodine labeled metaiodobenzylguanidine (MIBG) is the most effective method to screen cardiac pheochromocytomas. It is very useful to identify the tumor and also detect the presence of metastasis.
• Echocardiogram: transthoracic echocardiogram (TTE) is less sensitive than transesophageal echocardiogram (TEE) as tumors are often retro-pericardiac. When the tumor is firmly and extensively adherent to the pericardium, both of them are less sensitive.
• Magnetic Resonance Imaging (MRI): cardiac MRI is very sensitive compared to CT scan and echocardiogram for localization. It can also identify the relation of the tumor to the surrounding structures.
• Cardiac angiogram (cardiac catheterization): This is indispensable pre-operative imaging of CP. It can localize both the tumor and the feeding vessels.

In summary: MIBG, MRI, and coronary angiogram are indispensable pre-operative imaging modalities for tumor localization after laboratory confirmation.

The most effective treatment of cardiac pheochromocytomas is surgical resection.[9][10] However, blood pressure has to be controlled pre-operatively. Blood pressure normalization can be achieved with alpha-blockers (doxazosin, urapidil, phenoxybenzamine) initiating 2 to 3 weeks prior to the surgery. Other medications that can be used are calcium channel blockers (amlodipine, nifedipine) and angiotensin-converting enzyme inhibitors (ramipril).[11] It is very important to avoid using beta blockers until good blood pressure control with alpha-blockers. Isolated beta-blocker use can cause a catecholamine storm and hypertensive crisis.[11] It is recommended to start beta-blockers 2 days prior to surgery to control heart rate. There is no known role for chemoradiation.[3]

In general, differential diagnosis of pheochromocytomas is broad, and these include but not limited to adrenal pheochromocytomas, hyperthyroidism, thyroid storm, cardiac arrhythmias, carcinoid tumor, migraine, stroke, medullary thyroid carcinoma, mastocytosis, etc.

In patients with a confirmed cardiac mass, the differential diagnosis may include pericardial mass, abscess, or metastasis.

The most effective treatment of cardiac pheochromocytomas is surgical resection. 

The one- year and 5- year survival rate date of 91 patients who had benign CP were 98.2% and 78.8%, respectively.[2] Although data is limited, overall prognosis and recovery are quite good after complete resection. For malignant CP, the prognosis is not clear yet, as not enough data is available.

Complications can be related to either the disease itself or the procedure. Since it is a catecholamine-secreting tumor, if not treated, it can cause ischemic heart disease, myocardial infarction, cardiac arrhythmias, cardiomyopathy, pulmonary edema, stroke, and hypertensive crisis. The procedure is high risk. CP is a highly vascular tumor. In data of 100 patients, 5 died due to massive intraoperative bleeding.

An interprofessional approach including a cardiologist, a cardiothoracic surgeon, an oncologist, an electrophysiologist, an intensivist, an internist, and the nurse is required for proper care and management of patients with CP. The overall prognosis is quite good after total resection.